PUBLICATIONS

Dr. Alex Meves, distinguished dermatologist at the Mayo Clinic and a spokesperson for SkylineDx, discusses the challenges in diagnosing and treating melanoma and how a new molecular test called Merlin can help improve risk stratification and treatment decisions for patients with early-stage melanoma. Diagnosis and treatment have traditionally used tumor thickness as a primary risk factor. This molecular test measures the expression of genes in the tumor biopsy and can help determine the extent of surgery needed and whether additional therapies may be beneficial.

Alex explains, “My department, when I started to work here at Mayo, wanted me to do some translational research, and I had just come back from a postdoc in Germany, at the Max Planck Institute, and I was tasked to get some research going. And so I focused on melanoma because I thought at the time there wasn’t a lot of molecular research going on in melanoma that could be translated to patients. And so we started to develop biomarkers, sort of molecular tests that we could apply to tissue, and then help patients with.”

“Yes, so the problem that our research is focused on is what to do once you’re diagnosed with a melanoma. What you want to do is to match the right therapy to the right patient. That’s the goal. There are lots of melanomas that might not be very aggressive, and you don’t have to do a lot of treatment. And then there’s some melanoma that’s very aggressive, and you want to do lots of treatment, but it’s not always obvious which melanoma is low risk and which melanoma is high risk. And so this idea of risk stratification at diagnosis becomes very important to match therapy to patients.”

#skincancer #melanoma #SkylineDx #PersonalizedMedicine #PrecisionDiagnostics

Purpose

More than 80 % of patients with melanoma are diagnosed without nodal metastasis, but most of those who relapse or die from melanoma are initially diagnosed as low risk early-stage. Here we investigate the ability of the Merlin Assay to stratify patients who did not undergo sentinel lymph node biopsy (SLNB) for their risk of recurrence. Patients and methods: 930 patients with clinical stage I/II primary cutaneous melanoma from the University of Tuebingen diagnosed between 2000 and 2020 were analyzed. None of the patients included underwent SLNB. The Merlin Assay combines patient age at diagnosis, Breslow thickness, and gene expression of eight specific genes from the primary tumor. Risk output labels are High Risk and Low Risk.

Results

Clinicopathological gene expression profile (CP-GEP) identified 879 patients as Low Risk and 51 patients as High Risk. The 10-year RFS (HR 20.07; p <0.001) and DMFS (HR 19.39; p <0.001) were significantly higher in CP-GEP Low Risk versus High Risk patients. Similar results were observed in 10-year MSS (HR 35.85; p < 0.001). CP-GEP analysis of lentigo maligna melanoma and acral lentiginous melanoma showed that the performance of assay was independent of melanoma histological subtypes.

Conclusion

This study shows that CP-GEP has the potential to stratify patients with early-stage melanoma who did not undergo SLNB based on their risk of recurrence. Patients with CP-GEP Low Risk have a significantly better long-term survival. CP-GEP shows to be promising for guiding SLNB referral and may support melanoma care by optimizing personalized treatment plans and potential surveillance regimens.

Introduction:

Guidelines recommend sentinel lymph node biopsy (SLNB) for cN0 melanoma patients (pts) with a predicted risk of SLN metastasis ≥10% and considering SLNB for a 5-10% risk. A gene expression profile (GEP)-based test that accurately identifies pts with a low risk of SLN metastasis could refine pt selection for SLNB, but current guidelines advise against using GEP for SLN risk prediction absent prospective trial data. This blinded prospective study across nine US centers evaluated the performance of the CP-GEP test, combining clinicopathologic factors (age, Breslow thickness) with gene expression (GEP) of 8 genes for predicting SLN status in pT1-T3 cN0M0 cutaneous melanoma pts undergoing clinically indicated SLNB.

Methods:

GEP was performed on formalin-fixed, paraffin-embedded tissue from the primary tumor diagnostic biopsy. CP-GEP test results were reported in binary fashion as Low or High Risk. The primary outcome measure was negative predictive value (NPV) in Low Risk pts. Preplanned analyses included NPV assessment by T substage and age.

Results

GEP was performed successfully in 97.4% of samples. 1,686 T1-T3 pts with a successful CP-GEP test underwent SLNB (17.6% SLN-positive [SLN+]); 37% were classified as Low Risk by CP-GEP. Among all pts classified as Low Risk, 7.1% were SLN+ for an NPV of 92.9% (95% CI 90.6-94.8%). High Risk classification carried a 23.8% SLN+ rate. Most T1b pts (66.6%) were Low Risk, with a SLN+ rate of 5.1% (95% CI 3.0-9.2%) whereas High Risk T1b patients had a SLN+ rate 17.3% (11.7-24.2%). Fewer T2a pts were Low Risk (37.6%), with a SLN+ rate of 7.9% (95% CI 4.8-12.1%). In the pre-specified clinical stage IB subgroup (T1b-T2a), the SLN+ rate in Low Risk patients was 6.4% (95% CI 4.5-8.7%) and 18.7% (15.6-22.2%) for High Risk patients (Table). Model performance was consistent across age subgroups, with the SLN+ rate in Low Risk patients being 0% (95% CI 0-13.7%) for age <40 (n=145), 8.2% (95% CI 5.6-12.9%) for age 40-64 (n=744), and 6.2% (95% CI 3.9-9.4%) for age >64 (n=797).

Conclusion

In the first prospective multicenter blinded trial of a GEP prediction tool for SLN status, the CP-GEP test reliably identified pts with a <10% risk of SLN metastasis. For Stage IB patients the SLN+ rate was 3-fold greater for a High Risk vs Low Risk CP-GEP test. This approach has potential to more precisely estimate individual pt risk of harboring a SLN metastasis

Introduction

There is a pressing need for individualized prognostic markers to guide follow-up and adjuvant treatments in pT1a-4b cN0M0 melanoma patients. Previous validation studies have shown that the Merlin assay is a promising tool for risk assessment regarding nodal metastasis and risk of recurrence in this population.

Methods

We conducted a single-center academic retrospective study and included melanoma patients diagnosed between January 2018 and May 2024. Primary tumors were resected and followed by sentinel lymph node biopsy (SLNB). The Merlin™ test integrates CP variables age and Breslow thickness and the expression of eight genes from primary melanoma samples. The test produces a binary output: High Risk or Low Risk.

Results

51 pts were included, of which 27 female, with a median age at diagnosis of 65 years (range 26-90), median Breslow thickness of 1.5 mm (range 0.31-11.1) and a SLNB positivity rate of 15.7%. T-stagedistribution: pT1a was 1 pt, pT1b 9 pts, pT2a 20 pts, pT3a 6 pts, pT3b 5 pts, pT4a 2 pts, and pT4b 8 pts. Merlin assay classified 15 pts as Low Risk, and 36 pts as High Risk. After a median follow-up of 26 months (0-83), no recurrences were observed in the Low Risk group, compared to 8 recurrences in the High Risk group. Three-year relapse-free survival rate was 100% versus 68% (95% CI 19-87) in the Low- and High-risk groups, respectively (log rank, p=0.062). Patients were further stratified according to sentinel lymph node biopsy results. In pts with a Low Risk score, one positive sentinel node was detected. In the 36 pts with a high-risk score, 7 pts had a positive node, of which 5 had recurrent disease (3y RFS 28% [95% CI 0-62]). Conversely, only 3 recurrences were observed in the 29 high-risk pts with a negative SLNB (3y RFS-rate 89.7% [95% CI 62-100]). RFS of pts with a positive SLNB and Low Risk Merlin test was significantly lower as compared to all other groups (log rank, p<0.001). In this cohort, Merlin assay could have achieved a theoretic SLNB reduction rate of 29% with a NPV of 93.3%. SLNB identified 5 out of 8 relapses whereas CP-GEP captured all.

Conclusion

The predictive value of the Merlin assay for sentinel node positivity was confirmed in our single center retrospective case series. Risk assessment based on the Merlin assay and sentinel node status allows for risk stratification that deserves further investigation regarding personalized risk adapted management of cN0M0 melanoma patients.

Introduction

Guidelines recommend sentinel lymph node biopsy (SLNB) for cN0 melanoma patients (pts) with a predicted risk of SLN metastasis ≥10% and considering SLNB for a 5-10% risk. A gene expression profile (GEP)-based test that accurately identifies pts with a low risk of SLN metastasis could refine pt selection for SLNB, but current guidelines advise against using GEP for SLN risk prediction absent prospective trial data. This blinded prospective study across nine US centers evaluated the performance of the CP-GEP test, combining clinicopathologic factors (age, Breslow thickness) with gene expression (GEP) of 8 genes for predicting SLN status in pT1-T3 cN0M0 cutaneous melanoma pts undergoing clinically indicated SLNB.

Methods

GEP was performed on formalin-fixed, paraffin-embedded tissue from the primary tumor diagnostic biopsy. CP-GEP test results were reported in binary fashion as Low or High Risk. The primary outcome measure was negative predictive value (NPV) in Low Risk pts. Preplanned analyses included NPV assessment by T substage and age.

Results

GEP was performed successfully in 97.4% of samples. 1,686 T1-T3 pts with a successful CP-GEP test underwent SLNB (17.6% SLN-positive [SLN+]); 37% were classified as Low Risk by CP-GEP. Among all pts classified as Low Risk, 7.1% were SLN+ for an NPV of 92.9% (95% CI 90.6-94.8%). High Risk classification carried a 23.8% SLN+ rate. Most T1b pts (66.6%) were Low Risk, with a SLN+ rate of 5.1% (95% CI 3.0-9.2%) whereas High Risk T1b patients had a SLN+ rate 17.3% (11.7-24.2%). Fewer T2a pts were Low Risk (37.6%), with a SLN+ rate of 7.9% (95% CI 4.8-12.1%). In the pre-specified clinical stage IB subgroup (T1b-T2a), the SLN+ rate in Low Risk patients was 6.4% (95% CI 4.5-8.7%) and 18.7% (15.6-22.2%) for High Risk patients (Table). Model performance was consistent across age subgroups, with the SLN+ rate in Low Risk patients being 0% (95% CI 0-13.7%) for age <40 (n=145), 8.2% (95% CI 5.6-12.9%) for age 40-64 (n=744), and 6.2% (95% CI 3.9-9.4%) for age >64 (n=797).

Conclusion

In the first prospective multicenter blinded trial of a GEP prediction tool for SLN status, the CP-GEP test reliably identified pts with a <10% risk of SLN metastasis. For Stage IB patients the SLN+ rate was 3-fold greater for a High Risk vs Low Risk CP-GEP test. This approach has potential to more precisely estimate individual pt risk of harboring a SLN metastasis than by clinical stage alone, and thus inform shared surgeon-patient decision-making for SLNB.

Introduction

Sentinel lymph node biopsy (SLNB) is the gold standard for nodal assessment in staging cutaneous melanoma (CM) according to AJCC v8 guideline. More than 80% of pts are negative for nodal metastasis, but most pts who relapse or die from melanoma are initially diagnosed as ‘low risk’ early-stage. Previously we showed that the clinicopathological-gene expression profiling (CP-GEP) model can stratify stage I-II pts and pts who did not undergo SLNB in low and high-risk of recurrence (Amaral et al., EJC, 2023). Here we investigate CP-GEP ability to stratify pts who did not undergo SLNB for their risk of recurrence in substantial cohort.

Methods

We analysed formalin-fixed paraffin-embedded primary tumor samples of 930 pts with stage I/II CM diagnosed between 2000-2017, included in the Central Malignant Melanoma Registry, who did not receive SLNB. Tumors were analysed blinded to clinical outcome. The CP-GEP model used combines the expression of 8 genes (SERPINE2, GDF15, ITGB3, CXCL8, LOXL4, TGFBR1, PLAT and MLANA) by quantitative reverse transcription polymerase chain reaction with age and Breslow thickness to obtain a binary output: CP-GEP Low- or High-Risk. Relapse-free survival (RFS), distant metastasis free survival (DMFS) and Melanoma Specific Survival (MSS) were evaluated using Kaplan-Meier curves.

Results

We included 930 pts (stage IA-IIC). 41% were females, median age was 64-year-old, median Breslow thickness was 0.5 mm, the majority were not ulcerated (94%). For all pts, the 5-year RFS was 90.9%; 5-year DMFS was 96.9 and 5-year MSS was 97.5%. Median follow-up time was 55 months (RFS). CP- GEP identified 879 pts as Low-Risk and 51 pts as High-Risk. The 5-year RFS rate was 94.6% for CP-GEP Low-Risk pts versus 26.6% for CP-GEP High-Risk patients (HR 25.08; p<0.001). 5-year DMFS was 98.6% vs 62.1% (HR 35.39; p<0.001) for CP-GEP Low-Risk and High-Risk pts, respectively. The 5-year MSS was 99.4% for Low-Risk and 61.7% for High-Risk pts (HR 71.05; p<0.001), capturing 12 out of 16 melanoma specific deaths in the CP-GEP High-Risk group.

Conclusion

This comprehensive study shows that CP-GEP has the potential to stratify pts with early-stage melanoma who did not undergo SLNB based on their risk of recurrence. Pts with CP-GEP Low-Risk have a good long-term survival while pts with CP-GEP High-Risk have a high risk of recurrence. CP-GEP may have the potential to stratify pts beyond SLNB.

Introduction

Currently, sentinel lymph node biopsy (SLNB), is still considered the most appropriate, standard of care, tool to stage melanoma patients, who present with newly diagnosed stage IB-II melanomas. With the developments in systemic therapy, specifically the shift towards earlier stages of disease, the use of the minimally invasive, but nonetheless invasive, SLNB is once again being scrutinized. The aim of the current study was to validate the diagnostic accuracy of the clinicopathological-gene expression profile (CP-GEP) model on an independent cohort from the Netherlands Cancer Institute.

Methods

Patients who presented with newly diagnosed clinical stage I/II melanoma, who presented at the Netherlands Cancer Institute (NKI; Amsterdam, the Netherlands), between 2007 and 2015, were eligible for this current study. Data were prospectively collected in an institutional database and were retrospectively analysed. Data cut-off for follow-up was January 2022. The CP-GEP included the RNA expression of eight target genes associated with tumor development (i.e. MLANA, GDF15, CXCL8, LOXL4, TGFBR1, ITGB3, PLAT and SERPINE2) and two housekeeping genes in combination with CP variables Breslow thickness and age.

Results

A total of 252 patient’s samples and clinical data were submitted. In 9 patients, the CP-GEP was unable to be performed, in n=4 this was due to the lack of being able to identify the housekeeping genes (1.6%) and n=5 due to both a lack of housekeeping and target gene expression (2.0%). The final analysis was performed on the remaining 243 cases. Median age was 57 years old (IGR 46 – 67), 51.4% was female. Breslow thickness was 1.8 mm (IQR 1.3-2.95) and 53 patients demonstrated involvement of the SLNB (21.8%). Over half of the patients were diagnosed with pT2 tumour of which 44.9% pT2a. Median follow-up was 83 months. CP-GEP identified 68 (28%) patients as CP-GEP Low Risk and 175 (72%) as High Risk. The sensitivity of CP-GEP was 92.5%, specificity was 33.7%, PPV was 28.0% and NPV was 94.1% for all comers (T1-T4). The CP-GEP had the best performance in T1 with a NPV 95.2% and SLNB reduction rate (RR) of 80.8%, and in the pT1b-pT2a melanomas with a NPV of 93.3% and a SLNB RR of 45.5%. In terms of long-term survival, the 5-year RFS of CP-GEP low-risk was 89.6% (95% CI: 79.5-94.9) vs. 76.8% (95% CI: 69.8-82.4) for CP-GEP high-risk patients.

Conclusion

This CP-GEP model demonstrated good prognostic performance in an independent validation cohort, particularly for pT1b-pT2a melanoma patients and thus should be considered added value to current standard of care practice.

Introduction

Sentinel lymph node biopsy (SLNB) is an important tool for staging clinically node negative patients with cutaneous melanoma (CM). Having a negative SLN indicates a favorable prognosis, however many of these early-stage CM patients will relapse or even die of melanoma. Risk stratification of these early-stage patients is warranted. Previously Eggermont (2020), Mulder (2022) and Amaral (2023) showed that the CP-GEP model (Merlin Assay) can risk stratify CM patients in terms of risk of recurrence and melanoma specific survival.

Aim: To validate CP-GEP’s ability to risk stratify melanoma patients based on long-term survival in a three-continent study.

Methods

• 522 clinically node negative stage I-III CM patients that underwent SLNB during 2007-2017 at Peter MacCallum Cancer Centre and Alfred Health (MRV, Victoria, Australia), Heidelberg University (Germany) or University of Louisville (USA).
• CP-GEP combines Breslow thickness and patient’s age at diagnosis with the expression of eight genes from the primary tumor and provides a binary output: High Risk or Low Risk.
• Primary endpoints: 5-year Relapse-Free Survival (RFS), Distant Metastasis-Free Survival (DMFS), Melanoma-Specific Survival (MSS) and Overall Survival (OS). Median follow-up time was 72 months.

Conclusion

CP-GEP can risk stratify CM patients by their long-term survival across all clinical stages

• CP-GEP Low Risk patients have a favorable long-term survival, while CP-GEP High Risk patients have a high risk of recurrence
•  CP-GEP may be used to support clinical decision-making in melanoma clinical care

Introduction:

Guidelines recommend staging melanoma patients (pts) with sentinel lymph node biopsy (SLNB) for a predicted risk of SLN metastasis ≥10% and considering SLNB for 5-10% risk. A gene expression profile (GEP)-based test that accurately identifies pts with a low risk of SLN metastasis would help refine pt selection for SLNB, but current guidelines advise against using GEP for SLN risk prediction absent prospective trial data. This blinded prospective multicenter study evaluated the performance of a test combining clinicopathologic factors (age, Breslow thickness) with an 8-gene GEP (CP-GEP test) for predicting SLN status in pT1-T3 cN0M0 cutaneous melanoma pts undergoing clinically indicated SLN biopsy.

Methods:

The CP-GEP was performed on formalin-fixed, paraffin-embedded tissue from the primary tumor biopsy and results recorded in binary fashion as Low or High Risk. The primary endpoint was negative predictive value (NPV) in Low Risk pts. Preplanned analyses included NPV assessment by T substage and age.

Results:

The GEP was successfully performed in 97.4% of samples. 1,686 pts with a successful GEP underwent SLNB (17.6% SLN-positive); 37% were classified as Low Risk by CP-GEP. Among all pts classified as Low Risk, the SLN was positive in 7.1% for an NPV of 92.9% (95% CI 90.6-94.8%). High Risk pts were SLN positive in 23.8%. Most T1b pts (66.6%) were Low Risk, with an NPV of 94.9% (95% CI 91.8%-97.0%); fewer T2a pts were Low Risk (37.6%), with an NPV of 92.7% (95% CI 87.9-95.2%). Test performance was consistent across age subgroups.

Conclusion:

In the first prospective multicenter blinded trial of a GEP prediction tool for SLN status, the CP-GEP test reliably identified pts with <10% risk of SLN metastasis, suggesting its potential to more precisely estimate individual pt risk of a SLN metastasis and inform shared decision-making for SLNB.

Introduction:

• In melanoma, accurate identification of T1a patients who should consider sentinel lymph node biopsy (SLNB) is important.
  NCCN guidelines recommended consideration of SLNB for T1a melanoma patients with adverse features such as age <40 years, lymphovascular invasion, and/or ≥2 mitoses/mm².
• This study evaluates the clinical utility of the Merlin Assay (CP-GEP model that uses clinicopathologic and gene expression variables) in stratifying T1a melanoma patients for SLNB referral, including those without adverse features.

Methods:

• This is a retrospective analysis of a cohort of 153 T1a melanoma patients from 11 centers diagnosed between 2007 and 2021 who underwent SLNB at the discretion of the treating surgeon.
• CP-GEP performance was assessed by comparing the SLN positivity rate (pre-test SLN+ rate) in the entire cohort to the post-test SLN+ rates for CP-GEP Low Risk and High Risk patients.

Results:

• For 153 T1a melanoma patients, the overall SLN positivity rate was 3.3%.
• CP-GEP identified 134 patients as Low Risk (88%) with a post-test SLN+ rate of 1.5%. In contrast, CP-GEP identified 19 patients as High Risk (12%) with a post-test SLN+ rate of 15.8%.
• In T1a melanoma patients, CP-GEP achieved an SLNB reduction rate of 87.6% at a NPV of 98.5%.
• In 49 patients with a least one adverse feature, CP-GEP identifies 37 Low Risk patients with a post-test SLN+ rate of 0% (Figure 1).
• In 104 patients without any adverse feature, CP-GEP identifies 7 High Risk patients with a post-test SLN+ rate of 14.3% (Figure 1).

Conclusions:

• Merlin Assay may support in risk stratifying cutaneous melanoma patients with T1a tumors.
• CP-GEP can support referral of T1a for SLNB surgery independent of traditional adverse features.
• CP-GEP can identify patients with T1a melanoma who are at high risk of SLN metastases who otherwise would not be offered an SLNB based on lack of adverse features. On the other hand, CP-GEP may deselect thin melanoma patients with adverse features who are at low risk for nodal metastases.

Introduction & Objectives:

Sentinel lymph node biopsy (SLNB) is still the gold standard for nodal assessment used in the clinical staging of cutaneous melanoma (CM) pts by AJCC v8. Recently, we showed in a small cohort that CP-GEP also has the potential to risk stratify pts who did not undergo SLNB in low and high-risk for recurrence (Amaral et al, EJC 2023). SLNB may be challenging in pts with head and neck (H&N) melanoma, due to the regional course of cranial nerves and lymphatic drainage. Here we focus on the ability of CP-GEP to stratify pts with H&N melanoma, who did not undergo SLNB, for their risk of recurrence.

Materials & Methods:

We analyzed formalin-fixed paraffin-embedded primary tumor samples of 451 pts with stage I/II CM diagnosed between 2000-2017, included in the Central Malignant Melanoma Registry, who did not receive SLNB. The CP-GEP model used combines the expression of 8 genes (SERPINE2, GDF15, ITGB3, CXCL8, LOXL4, TGFBR1, PLAT and MLANA) by quantitative reverse transcription polymerase chain reaction with age and Breslow thickness to obtain a binary output: CP-GEP Low- or High-Risk. Relapse-free survival (RFS), distant metastasis free survival (DMFS) and Melanoma Specific Survival (MSS) were evaluated using Kaplan-Meier curves.

Results:

We included 451 pts (stage IA-IIC), 40% were females, median age was 63-year-old, median Breslow thickness was 0.5 mm and 20% (n=90) were diagnosed with H&N melanoma. An interim analysis was performed on samples from 159 pts showing the following survival: 5-year RFS 85.8%, DMFS 94.1 and MSS 95.7%. Survival analysis for pts with H&N melanoma is currently being conducted and will be presented at the time of the congress.

Conclusions:

CP-GEP has the potential to risk stratify pts with early-stage melanoma that did not undergo SLNB based on their risk for long-term survival. Pts with CP-GEP Low-Risk have a good long- term survival compared to High-Risk pts even though SLN status was not assessed, and this seems to be true also for pts with H&N melanoma. This may allow the clinicians to skip SLNB in this difficult anatomic localization.

Background:

Sentinel lymph node biopsy (SLNB) is
the gold standard for nodal assessment in staging
cutaneous melanoma (CM) according to AJCC v8.
80-85% of patients (pts) do not have nodal metastasis,
but most pts who relapse or die from melanoma are
initially diagnosed as ‘low risk’ early-stage. We
showed that the clinicopathological-gene expression
profiling (CP-GEP) model can stratify pts with negative
SLNB for their risk of recurrence.

Aim:

To demonstrate the ability of CPGEP
to stratify pts who did not undergo
SLNB for their risk of recurrence in an
expanded cohort.

Methods:

formalin-fixed paraffin-embedded
primary tumor samples of pts with CM diagnosed
between 2000-2020 who did not undergo SLNB
were analyzed. The CP-GEP model used combines
the expression of 8 genes (SERPINE2, GDF15,
ITGB3, CXCL8, LOXL4, TGFBR1, PLAT and MLANA)
by qPCR with age and Breslow thickness to obtain
a binary output: CP-GEP Low-Risk or High-Risk.
Relapse-free survival (RFS), distant metastasis free
survival (DMFS) and Melanoma Specific Survival
(MSS) were evaluated using Kaplan-Meier curves.
Median follow-up time was 5 years.

Background

• Sentinel lymph node biopsy (SLNB) is an invasive procedure used for accurate staging and optimal management
• SLNB is recommended for melanomas with Breslow thickness > 1.0 mm and should be discussed for patients with thin melanomas
• Overall rate of positive SLNBs is relatively low, ranging from 15% to 20%
• CP-GEP model serves as a deselection tool by identifying patients that
• Sentinel lymph node biopsy (SLNB) is an invasive procedure used for accurate staging and optimal management
• SLNB is recommended for melanomas with Breslow thickness > 1.0 mm and should be discussed for patients with thin melanomas
• Overall rate of positive SLNBs is relatively low, ranging from 15% to 20%
• CP-GEP model serves as a deselection tool by identifying patients that do not have nodal metastasis and can therefore forgo SLNB

Objectives

To summarise the findings of multiple external validation studies across various countries to assess the overall predictive performance of the CP-GEP model and examine potential heterogeneity between validation cohorts

Methods

• External validation studies assessing the CP-GEP model from 2020-2024
• True positive (TP), false positive (FP), true negative (TN), false negative (FN) values were extracted from each study to measure the predictive utility of the model (sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and SLNB reduction rate (RR)
• Pooled estimates were derived using a random-effects (RE) model
• Risk of bias: Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool
• SLNB reduction rate (RR) represents the proportion of patients that received a low-risk CP-GEP result and could therefore safely forgo SLNB

Results

• The overall pooled sensitivity was 93% and NPV was 95% across all primary tumour classification groups
• Subgroup analysis (pT1 – pT4) revealed that the model performed best for pT2 melanomas
• Results for pT1 melanomas could not be reliably interpreted as substantial heterogeneity was observed
• pT3 and pT4 melanomas are unlikely to benefit from the model as they have high risk for nodal metastasis and would usually be recommended to undergo SLNB

Conclusions

• The CP-GEP model demonstrated the hallmarks of an effective deselection tool for SLNB, particularly in patients with pT2 melanomas
• Additional research into pT1 melanomas with greater sample sizes will be crucial in determining the true predictive utility of the model for this subgroup

Background

Sentinel lymph node biopsy (SLNB) for head and neck melanomas involves complex challenges due to intricate lymphatic networks and delicate anatomic structures. The Merlin Assay (CP-GEP), merging clinicopathologic data with gene expression profiling, offers a non-invasive method to identify patients who have a low risk for nodal metastasis, potentially sparing these low-risk patients from surgical procedures.

Methods

This study evaluated 250 clinically node-negative patients with stage I, II, or III melanoma from the Mayo Clinic and University Hospitals Cleveland Medical Center who had tumors in the head and neck region diagnosed between 2004 and 2021. All the patients underwent SLNB. The Merlin Assay, using the CP-GEP model, combines patient age at diagnosis, Breslow thickness, and gene expression of eight specific genes from the primary tumor to predict the risk of nodal metastasis.

Results

The SLNB positivity rate was 14% overall, and CP-GEP predicted a possible 40.8% reduction in SLNB procedures with a negative predictive value (NPV) of 98%. For 215 SLNB-negative patients (5-year recurrence-free survival [RFS] of 76.9%, distant metastasis-free survival [DMFS] of 84.3%, and melanoma-specific survival [MSS] of 90.6%), CP-GEP improved risk stratification by identifying 100 patients as low risk with 5-year RFS of 86.1%, DMFS of 92.7%, and MSS of 95.3%. Among 167 T1–T2 patients, the SLNB positivity rate was 8.4%, and CP-GEP achieved an SLNB reduction rate of 56.3% with an NPV of 98.9%.

Conclusions

The Merlin Assay effectively categorizes head and neck melanoma patients by risk, enabling more accurate clinical decision-making regarding SLNB and follow-up evaluation, especially for early-stage melanoma patients.

Introduction & Objectives:

Sentinel lymph node biopsy (SLNB) is still the gold standard for nodal assessment used in the clinical staging of cutaneous melanoma (CM) pts by AJCC v8. Recently, we showed in a small cohort that CP-GEP also has the potential to risk stratify pts who did not undergo SLNB in low and high-risk for recurrence (Amaral et al, EJC 2023). SLNB may be challenging in pts with head and neck (H&N) melanoma, due to the regional course of cranial nerves and lymphatic drainage. Here we focus on the ability of CP-GEP to stratify pts with H&N melanoma, who did not undergo SLNB, for their risk of recurrence.

Materials & Methods:

We analyzed formalin-fixed paraffin-embedded primary tumor samples of 451 pts with stage I/II CM diagnosed between 2000-2017, included in the Central Malignant Melanoma Registry, who did not receive SLNB. The CP-GEP model used combines the expression of 8 genes (SERPINE2, GDF15, ITGB3, CXCL8, LOXL4, TGFBR1, PLAT and MLANA) by quantitative reverse transcription polymerase chain reaction with age and Breslow thickness to obtain a binary output: CP-GEP Low- or High-Risk. Relapse-free survival (RFS), distant metastasis free survival (DMFS) and Melanoma Specific Survival (MSS) were evaluated using Kaplan-Meier curves.

Results:

We included 451 pts (stage IA-IIC), 40% were females, median age was 63-year-old, median Breslow thickness was 0.5 mm and 20% (n=90) were diagnosed with H&N melanoma. An interim analysis was performed on samples from 159 pts showing the following survival: 5-year RFS 85.8%, DMFS 94.1 and MSS 95.7%. Survival analysis for pts with H&N melanoma is currently being conducted and will be presented at the time of the congress.

Conclusions:

CP-GEP has the potential to risk stratify pts with early-stage melanoma that did not undergo SLNB based on their risk for long-term survival. Pts with CP-GEP Low-Risk have a good longterm survival compared to High-Risk pts even though SLN status was not assessed, and this seems to be true also for pts with H&N melanoma. This may allow the clinicians to skip SLNB in this difficult anatomic localization.

Introduction

Primary cutaneous melanoma (CM) of the head and neck often yields false-negative results from sentinel lymph node biopsies (SLNB). Consequently, these melanomas exhibit higher recurrence rates than those on other body parts. In this study, we investigate the capability of CP-GEP to stratify patients’ risk for nodal metastasis and evaluate their long-term survival outcomes.

Methods

Patients with primary CM of the head and neck who underwent SLNB between 2004 and 2021 at two US centers were included in this study. CP-GEP integrates Breslow thickness, the patient’s age at diagnosis, and the expression of eight genes from the primary CM tissue. The CP-GEP model produces a binary output: High Risk or
Low Risk.

Results

Out of 250 head and neck CM patients included in the analysis, there was a 14.0% SLNB positivity rate. CP-GEP classified 147 patients (58.8%) as High Risk. These patients exhibited a higher SLNB positivity rate of 22.4% and accounted for 14 of the 19 melanoma-specific deaths (73.7%). Meanwhile, CP-GEP categorized 103 patients as Low Risk, leading to a 41.2% reduction in SLNB with a Negative Predictive Value (NPV) of 98.1%. The five-year Melanoma-Specific Survival (MSS) rates were 82.4% for High Risk patients and 95.5% for Low Risk patients.

Conclusion

CP-GEP has the potential to categorize primary CM patients of the head and neck based on their risk for nodal metastasis and long-term survival outcomes. Notably, CP-GEP can help identify patients with tumors in surgically challenging locations who potentially may avoid SLNB surgery, while more accurately pinpointing those truly at risk for melanoma-specific death.

Introduction

Sentinel lymph node biopsy (SLNB) is still the gold standard for nodal assessment, even though 80-85% of patients return negative for metastases. Also, most patients who relapse or die from melanoma are initially diagnosed as early-stage primary cutaneous melanoma (CM) patients. Here, we report the ability of CP-GEP to risk stratify patients for nodal metastasis and evaluate their long-term survival outcome.

Methods

Primary CM patients undergoing SLNB as part of usual care between 2007 and 2017 – University Hospitals Cleveland Medical Center. The Merlin assay that uses the CP-GEP model combines Breslow thickness and patients’ age at diagnosis with the expression of eight genes from the primary CM tissue – binary output: High Risk or Low Risk.

Results

176 patients were included for analysis with a 12.5% SLNB positivity rate. CP-GEP identified 66 patients as Low Risk – achieving an SLNB reduction rate of 37.5% at an NPV of 94%. For CP-GEP Low Risk patients, the five-years RFS, DMFS and MSS rates were 93.6%, 96.6% and 98% respectively. CP-GEP stratified 110 patients as High Risk (62.5%), having a higher SLNB positivity rate of 16.4% and capturing 21 out of 25 recurrences (84%). CP-GEP High Risk patients had five-years RFS, DMFS and MSS rates of 79.4%, 83.1% and 91.4% respectively.

Conclusion

CP-GEP improves risk stratification for nodal metastasis and disease recurrence, thereby supporting clinical decision making and optimizing healthcare resources. Specifically, recurrence events may be more effectively captured by CP-GEP as compared to current standard of care.

Intro:

The CP-GEP model (Merlin Assay) is able to identify cutaneous melanoma (CM) patients with a low risk of nodal metastasis undergoing sentinel lymph node biopsy (SLNB). Long-term follow-up (LTFU) for CM patients stratified by CP-GEP has been previously reported in multiple independent European cohorts to accurately stratify patients by their risk of recurrence. Here, we report the LTFU of patients classified as low and high Risk by CP-GEP in a combined US-based multi-center cohort.

Methods:

This is a retrospective study of CM patients undergoing SLNB as part of usual care at six centers. Using primary melanoma tissue, the CP-GEP model stratified patients as high or low risk of recurrence. The primary aim was to assess the 5-year recurrence-free survival (RFS), distant metastasis-free survival (DMSF), and melanoma specific-free survival (MSS) of CP-GEP high risk vs. low risk patients. Survival was assessed by Kaplan–Meier curves, stratified on CP-GEP low risk vs. high risk.

Results:

A total of 594 CM patients (317 Stage I, 164 Stage II and 109 Stage III) were included. Median follow-up was 52 months. CP-GEP classified 198 (33.3%) patients as low risk and 396 (66.7%) as high risk. CP-GEP low risk patients had 5-yrs RFS, DMFS and MSS of 92.4%, 96.9%, and 98.2% respectively. CP-GEP high risk patients had 5-yrs RFS, DMFS and MSS of 72.2%, 82.9%, and 88%, respectively. CP-GEP identified 16 patients (14.9%) of the 107 patients with a positive SLNB and LTFU data as low risk and 91 patients (85.0%) as high risk. The 5-yrs RFS rate for low risk and high risk Stage III patients were 91.7% and 44.6%, respectively. Furthermore, CP-GEP is able to classify SLNB negative patients (476) into low risk (37.8%) and high risk (62.2%) groups with 5-yrs RFS of 92.5% and 81.1%, respectively. CP-GEP risk stratification was independent from clinical staging for RFS and DMFS by multivariable analyses.

Conclusion:

In this multi-center US-based retrospective study, the CP-GEP model was able to stratify patients by their risk of recurrence. CP-GEP low risk patients showed a highly favorable outcome versus CP-GEP high risk patients, who have a nearly five times higher risk of recurrence. Therefore, this molecular prognostic test can provide valuable information in personalized treatment and surveillance recommendations.

Sentinel lymph node biopsy (SLNB) is recommended for patients with >pT1b cutaneous melanoma, and should be considered and discussed with patients diagnosed with pT1b cutaneous melanoma for the purpose of staging, prognostication and determining eligibility for adjuvant therapy. Previously, the clinicopathologic and gene expression profile (CP-GEP, Merlin Assay®) model was developed to identify patients who can forgo SLNB because of a low risk for sentinel node metastasis. The aim of this study was to evaluate the clinical use and implementation of the CP-GEP model in a prospective multicenter study in the Netherlands. Both test performance and feasibility for clinical implementation were assessed in 260 patients with T1-T4 melanoma. The CP-GEP model demonstrated an overall negative predictive value of 96.7% and positive predictive value of 23.7%, with a potential SLNB reduction rate of 42.2% in patients with T1-T3 melanoma. With a median time of 16 days from initiation to return of test results, there was sufficient time left before the SLNB was performed. Based on these outcomes, the model may support clinical decision-making to identify patients who can forgo SLNB in clinical practice.

Background:

Sentinel lymph node biopsy (SLNB) is used to staging and guide subsequent management of melanoma. However, proper patient selection for SLNB is challenging; approx. 80% of all SLNB are negative, with even higher negative rates when looking only at thin melanoma (T1) which account for the vast majority of cases. The clinicopathological and gene expression profile model (CP-GEP) was developed to identify low risk melanoma patients who may safely forgo SLNB. The CP-GEP combines Breslow thickness and patient age with the expression of eight genes to classify patients as high or low-risk for nodal metastasis. This study presents data from an independent validation of the CP-GEP in a multicentre Danish cohort.

Material and Method:

Archived formalin-fixed paraffin-embedded primary cutaneous melanoma tissue from 537 T1-T3 melanoma patients was collected and analysed with CP-GEP. The patients had undergone SLNB between 2010 and 2015 at either of two university clinics in Denmark. The CP-GEP result was compared with the SLNB result, calculating the diagnostic value of CP-GEP for SLNB metastasis.

Results:

Median age at diagnosis was 58 years (IQR 44-70) and median Breslow thickness was 1.3 mm (IQR 0.95-1.82). The distribution of T1, T2 and T3 melanoma was 32.8%, 46.9% and 20.3%, respectively. The SLNB positivity rate was 18.1%. The CP-GEP model identified 219 (40.8%) patients as having a low risk for nodal metastasis with a negative predictive value (NPV) of 91.3%. When analysing the T1 subgroup (n=176) the CPGEP low risk rate was 72.7% with a NPV of 94.5%.

Conclusion:

The CP-GEP identifies most patients at low risk for SN metastasis, especially in patients with T1 melanoma. Results are in line with previous retrospective validation studies on European and US cohorts. This study, however, contains the largest T1 subgroup validation with a potentially very high SLNB reduction rate.

Background

Sentinel lymph node biopsy (SLNB) is the standard procedure for staging in primary cutaneous melanoma and is used to guide subsequent management. It is, however, an invasive procedure with associated risks and proper patient selection for SLNB remains a challenge; approx. 80% of all SLNB are negative, with even higher negative rates when looking only at thin melanoma (T1) which account for the vast majority of cases. The clinicopathological and gene expression profile (CP-GEP) model was developed to identify low risk melanoma patients who may safely forgo SLNB. The CP-GEP model combines Breslow thickness and patient age with the expression of eight genes to classify patients as high or low-risk for nodal metastasis. This study presents data from an independent validation of the CP-GEP model in a multicenter Danish cohort.

Materials and Methods

Archived formalin-fixed paraffin-embedded primary melanoma tissue from 537 T1-T3 cutaneous melanoma patients was collected and analysed with CP-GEP in a prospectively designed study. The patients had undergone SLNB between 2010 and 2015 at either of two university clinics in Denmark. The CP-GEP result was compared with the SLNB result, calculating the diagnostic value of CP-GEP for SLNB metastasis.

Results

Median age at diagnosis was 58 years (interquartile range [IQR] 44-70) and median Breslow thickness was 1.3mm (IQR 0.95-1.82). The distribution of T1, T2 and T3 melanoma was 32.8%, 46.9% and 20.3%, respectively. The SLNB positivity rate was 18.1%. The CP-GEP model identified 219 (40.8%) patients as having a low risk for nodal metastasis with a NPV of 91.3%. When analysing the T1 subgroup (n=176) the CP-GEP low risk rate was 72.7% with an NPV of 94.5%.

Conclusion

The CP-GEP model accurately identifies patients at low risk for SN metastasis, and especially in patients with T1 melanoma. Results are in line with previous retrospective validation studies on European and US cohorts, however, this study contain the largest T1 subgroup validation with a potential very high SLNB reduction rate found for this subgroup. The CP-GEP is a promising risk stratification tool for melanoma patients, potentially preventing unnecessary surgery in a large group of patients.

Background:

Sentinel lymph node biopsy (SLNB) is the standard procedure for staging in primary
cutaneous melanoma and is used to guide subsequent management. It is, however, an invasive
procedure with associated risks and proper patient selection for SLNB remains a challenge;
approx. 80% of all SLNB are negative, with even higher negative rates when looking only at thin
melanoma (T1) which account for the vast majority of cases. The clinicopathological and gene
expression profile (CP-GEP) model was developed to identify low risk melanoma patients who
may safely forgo SLNB. The CP-GEP model combines Breslow thickness and patient age with the
expression of eight genes to classify patients as high or low-risk for nodal metastasis.
This study presents data from an independent validation of the CP-GEP model in a multicenter
Danish cohort.

Materials and Methods:

Archived formalin-fixed paraffin-embedded primary melanoma tissue
from 537 T1-T3 cutaneous melanoma patients was collected and analysed with CP-GEP in a
prospectively designed study. The patients had undergone SLNB between 2010 and 2015 at
either of two university clinics in Denmark. The CP-GEP result was compared with the SLNB
result, calculating the diagnostic value of CP-GEP for SLNB metastasis.

Results:

Median age at diagnosis was 58 years (interquartile range [IQR] 44-70) and median
Breslow thickness was 1.3mm (IQR 0.95-1.82). The distribution of T1, T2 and T3 melanoma was
32.8%, 46.9% and 20.3%, respectively. The SLNB positivity rate was 18.1%. The CP-GEP model
identified 219 (40.8%) patients as having a low risk for nodal metastasis with a NPV of 91.3%.
When analysing the T1 subgroup (n=176) the CP-GEP low risk rate was 72.7% with an NPV of
94.5%.

Conclusion:

The CP-GEP model accurately identifies patients at low risk for SN metastasis, and
especially in patients with T1 melanoma. Results are in line with previous retrospective validation
studies on European and US cohorts, however, this study contain the largest T1 subgroup
validation with a potential very high SLNB reduction rate found for this subgroup. The CP-GEP is
a promising risk stratification tool for melanoma patients, potentially preventing unnecessary
surgery in a large group of patients.

Introduction:

• In melanoma, accurate identification of T1a patients who should consider sentinel lymph node biopsy (SLNB) is important.
  NCCN guidelines recommended consideration of SLNB for T1a melanoma patients with adverse features such as age <40 years, lymphovascular invasion, and/or ≥2 mitoses/mm².
• This study evaluates the clinical utility of the Merlin Assay (CP-GEP model that uses clinicopathologic and gene expression variables) in stratifying T1a melanoma patients for SLNB referral, including those without adverse features.

Methods:

• This is a retrospective analysis of a cohort of 153 T1a melanoma patients from 11 centers diagnosed between 2007 and 2021 who underwent SLNB at the discretion of the treating surgeon.
• CP-GEP performance was assessed by comparing the SLN positivity rate (pre-test SLN+ rate) in the entire cohort to the post-test SLN+ rates for CP-GEP Low Risk and High Risk patients.

Results:

• For 153 T1a melanoma patients, the overall SLN positivity rate was 3.3%.
• CP-GEP identified 134 patients as Low Risk (88%) with a post-test SLN+ rate of 1.5%. In contrast, CP-GEP identified 19 patients as High Risk (12%) with a post-test SLN+ rate of 15.8%.
• In T1a melanoma patients, CP-GEP achieved an SLNB reduction rate of 87.6% at a NPV of 98.5%.
• In 49 patients with a least one adverse feature, CP-GEP identifies 37 Low Risk patients with a post-test SLN+ rate of 0% (Figure 1).
• In 104 patients without any adverse feature, CP-GEP identifies 7 High Risk patients with a post-test SLN+ rate of 14.3% (Figure 1).

Conclusions:

• Merlin Assay may support in risk stratifying cutaneous melanoma patients with T1a tumors.
• CP-GEP can support referral of T1a for SLNB surgery independent of traditional adverse features.
• CP-GEP can identify patients with T1a melanoma who are at high risk of SLN metastases who otherwise would not be offered an SLNB based on lack of adverse features. On the other hand, CP-GEP may deselect thin melanoma patients with adverse features who are at low risk for nodal metastases.

Abstract

Background:

AJCC v8 includes Breslow thickness and ulceration to subdivide stage I and II CM pts into risk groups. In light of the results from adjuvant therapy in stage II CM, it has been discussed that pts’ follow-up and eventually treatment should consider additional markers, namely CP-GEP, to further refine the risk classification provided by the AJCC v8. The aim of this single center study was to clinically validate a prognostic CP-GEP-based risk score for stage I/II CMs combining Breslow, age and the expression of 8 genes SERPINE2, GDF15, ITGB3, CXCL8, LOXL4, TGFBR1, PLAT and MLANA.

Methods:

All obtainable formalin-fixed paraffin-embedded primaries of stage I/II CMs with negative sentinel lymph node (SLN) from the Central Malignant Melanoma Registry of Germany diagnosed between 2000-2017 and archived in Tuebingen were included. Study hypothesis and protocol were prospectively formulated. Tumors were analyzed blinded to clinical outcome. Quantitative reverse transcription polymerase chain reaction of the 8 genes was performed and combined with age and tumor thickness to define CP-GEP low- vs. high-score groups. Relapse-free survival (RFS), distant metastasis free survival (DMFS) and overall survival (OS) were evaluated using Kaplan-Meier curves. CP-GEP score performance was tested using multivariate Cox regression adjusted for tumor thickness, ulceration and age.

Results:

We included 543 pts with Stage IA (n=78); IB (n=223); IIA (n= 123); IIB (n=73); IIC (n=46). 43% were females, median Breslow was 1.7mm and 25% of tumors had ulceration. The median follow-up was 78 months (IQR 47-116). 311 (57%) patients had a high-risk CP-GEP score. The 5-y RFS rate was 71% and 92% (HR 4.2; p<0.001), the 5-y DMFS rate was 86% and 96% (HR 4.35; p<0.001) and the 5-y OS was 85% and 95% (HR 3.2; p=0.001), respectively for high and low-risk CP-GEP score. In multivariate Cox regression analysis for RFS including Breslow thickness, ulceration and age, contribution of CP-GEP score remained independently significant (HR 2.75; p=0.0008) compared to age (HR 1.03; p<0.0007), Breslow (HR 1.21; p<0.0001) and ulceration (HR 1.37; p=0.1694).

Conclusions:

CP-GEP risk score is a non-invasive and independent prognostic model for risk of relapse in stage I/II melanoma validated in this study. It identifies SLN negative pts at high risk of relapse and should be considered for complementing AJCC classification and for inclusion in future clinical trials.

Background:

Approximately 70%-85% of patients who undergo sentinel lymph node biopsy (SLNb) show no nodal metastasis in the sentinel node (SN). The clinicopathological and gene expression profile (CP-GEP) model (Merlin Assay) was developed and validated to identify patients that may forgo the SLNb surgery due to their low risk for for nodal metastasis This study was initiated during the first wave of Covid-19 pandemic to allow for surgical triage on SLNb and evaluate the implementation of the Merlin assay in clinical practice.

Methods:

This study was conducted in four designated melanoma centers in the Netherlands. Patients (age > 18y) with newly diagnosed melanoma of the skin, eligible to undergo SLNb were screened for study inclusion. Main exclusion criteria was prior history of primary melanoma ( > T1b) in the past 5 years. After enrollment, tissue sections of the primary melanoma were centrally reviewed at the Erasmus MC Cancer Institute to determine Breslow thickness at primary diagnosis. FFPE tumor tissue was dispatched for molecular analysis of eight target genes known to play a role in cancer development. In combination with age, Breslow thickness, and GEP outcome, risk of having nodal metastasis was calculated. Results were binary presented as ‘CP-GEP low risk’ and ‘CP-GEP high risk’. SLNb status was used as gold standard for comparison.

Results:

A total of 177 patients were analyzed using the CP-GEP model. Median age was 64 years (IQR 52-73) Median Breslow thickness was 1.4mm (IQR 1.0-2.4). Of all patients 28.2% was diagnosed with T1, 40.7% with T2 and 20.9% with T3 melanoma. Corresponding positivity rate was 7%, 14% and 29% respectively. A total of 24 out of 177 patients had a positive SLNb. Median turn-around time from inclusion to CP-GEP result was 15 days. Overall 37.1.% of patients had a CP-GEP low risk profile. The CP-GEP model had a NPV of 94.6%. Conclusions: This is the first prospective multicenter implementation study for the Merlin assay. Results are in line with previous validation studies. The CP-GEP model could accurately identify patients at low risk for SN metastasis. Implementation in clinical practice is feasible based on current turn-around time. In the future, using the Merlin assay to deselect patients for SLNB may allow for a reduction of surgery in patients with melanoma.

Background:

For patients with cutaneous melanoma, sentinel lymph node biopsy (SLNB) provides important staging and prognostic information that guides surveillance and adjuvant systemic therapy decisions. At most centers, SLNB is indicated for patients with cutaneous melanoma with at least a 5% risk of having nodal metastases, typically melanomas ≥ 0.8 mm in thickness or thinner lesions with high-risk features such as elevated mitotic rate and/or ulceration. SLNB, generally involving a separate incision, does carry a small but measurable risk of complications including seroma, infection and rarely lymphedema, and most patients have negative sentinel lymph nodes. Currently, there is an unmet clinical need to identify patients who may safely forgo SLNB due to a low (<5%) risk of nodal metastasis, who otherwise meet established criteria for SLNB. Previously, a model consisting of gene expression profile (GEP) of the primary tumor combined with clinicopathological features (CP) has been developed to identify melanoma patients with a low risk of having a positive SLNB. The model has also been validated in multiple retrospective studies. The aim of the MERLIN_001 registry study is to prospectively validate the CP-GEP model in an independent multicenter cohort of primary cutaneous melanoma patients who undergo SLNB for standard indications.

Methods:

In the next two years, a total of 10 centers across the US will enroll 2,340 patients with clinically node-negative cutaneous melanoma undergoing SLNB using current guideline indications and will follow these patients for 5 years (ClinicalTrials.gov identifier: NCT04759781). Enrollment of patients started in September 2021 and 242 patients have been enrolled as of February 1, 2022. FFPE material from the initial melanoma biopsy will be used to assess the GEP of the primary melanoma. The CP-GEP probability scores will be expressed as a binary classification (Low Risk or High Risk for nodal metastasis) and will be compared to SLN pathology. Performance metrics for CP-GEP will be evaluated and will include: Negative Predictive Value, Positive Predictive Value, Sensitivity and Specificity, and the corresponding 95% confidence intervals. Risk for nodal metastasis will be calculated for Low Risk and High Risk CP-GEP patients. Finally, the performance of CP-GEP to stratify patients according to risk of recurrence (local, regional, distant, death) will also be studied, since data will be collected for up to 5 yrs. Clinical trial information: NCT04759781.

Introduction 

Approximately 70%-85% of patients who undergo sentinel lymph node biopsy (SLNB) show no nodal metastasis in the sentinel node (SN). CP-GEP, a model that combines clinicopathologic and gene expression variables from the primary tumor was developed and validated to identify patients that may forgo the SLNB surgery due to their low risk for SN-metastasis. This study was initiated during the first wave of COVID-19 pandemic to allow for surgical triage on SLNB and evaluate the implementation of the CP-GEP model in clinical practice. 

Methods 

This study was conducted in four designated melanoma centers in the Netherlands. Patients (age>18y) with newly diagnosed melanoma of the skin, eligible to undergo SLNB were screened for study inclusion. Main exclusion criteria was prior history of primary melanoma (>T1b) in the past 5 years. After enrollment, tissue sections of the primary melanoma were evaluated to determine Breslow thickness at primary diagnosis. FFPE tumor tissue was dispatched for molecular analysis of eight target genes known to play a role in cancer development. In combination with age, Breslow thickness, and GEP outcome, risk of having SN-metastasis was calculated. Results were binary presented as ‘CP-GEP Low Risk’ and ‘CP-GEP High Risk’. SLNB status was used as gold standard for comparison. 

Results 

A total of 177 patients were analyzed using the CP-GEP model. Median age was 64 years (IQR 52-73) Median Breslow thickness was 1.4mm (IQR 1.0-2.4). Of all patients 28.2% was diagnosed with T1, 40.7% with T2 and 20.9% with T3 melanoma. Corresponding positivity rate was 7%, 14% and 29% respectively. A total of 24 out of 177 patients had a positive SLNB (13.6%). Median turn-around time from inclusion to CP-GEP result was 15 days. Overall 37.1.% of patients had a CP-GEP Low Risk outcome. The CP-GEP model had a NPV of 94.6%. 

Conclusion 

This is the first prospective multicenter implementation study for the CP-GEP model. Results are in line with previous validation studies. The CP-GEP model could accurately identify patients at low risk for SN metastasis. Implementation in clinical practice is feasible based on current turn-around time. In the future, using the CP-GEP model to deselect patients for SLNB may allow for a reduction of surgery in patients with melanoma. 

Background:

The value of sentinel lymph node (SLN) surgery for patients with clinically node-negative T1b through T3 cutaneous melanomas is well-established. However, further precision in selecting patients for SLN surgery would be desirable as ∼80% of these patients have a negative SLN and might be spared complications potentially attributable to the addition of SLN surgery to wide local excision.

Objective:

The Merlin assay uses clinicopathologic variables and tumor gene expression profiling to identify low-risk patients who might avoid SLN surgery. Our aim was to assess the potential impact of this approach to patient triage on reducing postoperative complications.

Methods:

We utilized the Merlin test development cohort to determine complication rates for SLN procedures performed between 2004 and 2018 across Mayo Clinic tertiary care sites. Complications evaluated were lymphedema, seroma, infection/cellulitis, hematoma, and wound dehiscence. Patients who proceeded to completion lymph node dissection were excluded.

Results:

558 patients, median age 64.2 years, were included. The anatomic site of the primary tumor was head/neck in 144 (25.8%), trunk in 179 (32.1%), upper extremity in 147 (26.3%), lower extremity in 88 (15.8%). The overall 90-day complication rate attributed to SLN surgery was 17.4%. The most common complications were seroma (9.3%), infection/cellulitis (4.8%), and lymphedema (4.3% at one year). Complications were more common in patients with a lower extremity primary tumor location versus other locations. 51% of melanomas had a low-risk Merlin test result; SLNb reduction rates were similar in patients with and without surgery-related complications. Avoiding SLNb by Merlin testing lowers complication rates to a similar extent for all registered complications, specifically seroma by 68.8% and lymphedema by 58.1%. Moreover, post-procedure emergency department visits were reduced by 100%. Limitations: Retrospective data collection.

Conclusion:

SLN surgery is a safe procedure but carries a significant complication rate. Merlin testing might decrease the need for SLN surgery and the number of its associated complications.

Abstract 

Nodal pathological assessment via sentinel lymph node biopsy (SLNB) is important for primary cutaneous melanoma risk-stratification. The prognosis of patients with minimal sentinel node (SN) tumor burden – defined by the Rotterdam Criteria as a tumor burden of 0.1 mm or less – can be diverse. Therefore, optimal treatment of patients with minimal SN tumor burden is subject of an ongoing debate. CP-GEP assesses the risk of SLNB metastasis at diagnosis. Specifically, CP-GEP considers patient age at diagnosis, Breslow thickness and expression of eight genes in the primary tumor. Combination of these variables results in either of two risk labels: CP-GEP Low Risk or High Risk. Previously, we also investigated prognostic performance of CP-GEP in four independent cohorts from the US, the Netherlands, and Sweden totaling 1684 patients, 79 of whom had minimal SN tumor burden. The proportion of patients with minimal SN tumor burden was comparable between cohorts, 3-5%. We found that patients with minimal SN tumor burden from Sweden had a relapse risk comparable to SLNB positive patients, whereas Dutch and American patients had a relapse risk comparable to SLNB negative patients. We speculate that this discrepancy is caused by differences in histopathologic workup of SN. Of the 79 patients with minimal SN tumor burden, we observed recurrences in 2/17 (11.8%) CP-GEP Low Risk patients versus 19/62 (30.6%) recurrences in CP-GEP High Risk patients at a median follow-up time of 5.6 years. Further analysis of CP-GEP in larger cohorts is required to confirm observed trends. 

Background

Approximately 85% of melanoma patients who undergo a sentinel lymph node biopsy (SLNB) are node-negative. Melanoma incidence is highest in patients ≥65 years, but their SLNB positivity rate is lower than in younger patients. CP-GEP, a model combining clinicopathologic and gene expression variables, identifies primary cutaneous melanoma (CM) patients who may safely forgo SLNB due to their low risk for nodal metastasis. Here, we validate CP-GEP in a U.S. melanoma patient cohort.

Methods

A cohort of 208 adult patients with primary CM from the Mayo Clinic and West Virginia University was used. Patients were stratified according to their risk for nodal metastasis: CP-GEP High Risk and CP-GEP Low Risk. The main performance measures were SLNB reduction rate (RR) and negative predictive value (NPV).

Results

SLNB positivity rate for the entire cohort was 21%. Most patients had a T1b (34%) or T2a (31%) melanoma. In the T1-T2 group (153 patients), CP-GEP achieved an SLNB

RR of 41.8% (95% CI: 33.9-50.1) at an NPV of 93.8% (95% CI: 84.8-98.3). Subgroup analysis showed similar performance in T1-T2 patients ≥65 years of age (51 patients;

SLNB positivity rate, 9.8%): SLNB RR of 43.1% (95% CI: 29.3-57.8) at an NPV of 95.5% (95% CI: 77.2-99.9).

Conclusion

We confirmed the potential of CP-GEP to reduce negative SLNB in all relevant age groups. Our findings are especially relevant to patients ≥65 years, where surgery is often elective. CP-GEP may guide SLNB decision-making in clinical practice.

Background

For patients with primary cutaneous melanoma, sentinel lymph node biopsy (SLNB) is an important technique to assess disease stage and to guide adjuvant systemic therapy1. Around 80-85% of all SLNB procedures do not detect nodal metastasis. A model using clinicopathologic and gene expression variables (CP-GEP; Merlin Assay) has been introduced to identify patients that may safely forgo SLNB2 due to their low risk for nodal metastasis. CP-GEP combines Breslow thickness and patient age with the expression of eight genes to classify patients as High Risk or Low Risk for nodal metastasis.

Purpose

The aim was to independently validate the Merlin Assay in a population-based retrospective cohort.

Method

421 FFPE primary melanomas were analyzed for CPGEP which classified patients into Low risk and High risk for nodal metastasis. CP-GEP risk labels were compared to the known SLNB status.

Results

The median age was 60 years and 49% of the patients were females. Of the 421 patients, 335 patients (80%) were classified as CP-GEP High Risk and 86 (20%) as CP-GEP Low Risk for nodal metastasis. The overall SLNB positivity was 13%. Of the 86 CP-GEP Low Risk patients, CP-GEP could correctly identify 83 (96.5%) patients who were SLNB negative. For patients with T1-T2 tumors, the negative predictive value (NPV) was 96.5% and the SLNB reduction rate was 35.4%. For patients with T1-T3 tumors, the NPV was 96.5% and the SLNB reduction rate was 24.0%. All T4 tumors were classified as CP-GEP High Risk for nodal metastasis.

Conclusion

The CP-GEP model has been independently validated in a European retrospective patient cohort, and can be used to identify patients who may safely forgo SLNB procedure due to their low risk for nodal metastasis.

Background

In light of the current COVID-19 pandemic, avoiding unnecessary interventions and keeping patients out of the hospital becomes increasingly important. The CP-GEP model (Merlin Assay) has been developed and validated to identify patients with primary melanoma (pT1 b-pT3) that can safely forgo the sentinel lymph node biopsy (SLNB) due to their low risk for nodal metastasis. During the current pandemic, a prospective trial was conducted to assess the accuracy of using the CPGEP model to identify patients that have a low risk for nodal metastasis and therefore could forgo the SLNB.

Methods

During the COVID-19 pandemic, from July 2020 to February 2021, all newly diagnosed cutaneous melanoma (pT1 b-pT3) patients elected to undergo SLNB at the Erasmus MC Cancer Institute were included. Formalin-fixed paraffin embedded tissue (FFPE) from the primary melanoma tissue was analyzed using CP-GEP. The CP-GEP model combines patient age and Breslow thickness with the expression of eight target genes. Patients were classified as CP-GEP High Risk or CP-GEP Low Risk for having nodal metastasis.

Results

From all eligible patients (n=19), consent was obtained and FFPEs could be retrieved for further analysis. Patients had a median age of 53 years (interquartile range [IQR] 37 – 67) and median Breslow thickness was 2.0 mm (IQR 1,4-2.8). In two out of 19 patients, the surgeon determined preoperatively not to proceed with SLNB (as a result of locally advanced melanoma). Of the remaining 17 patients, five had a positive SLNB (e.g. nodal metastasis, 29.4% ). All SLNB positive patients (n=5) were identified by CP-GEP as being High Risk for nodal metastasis. Of all SLNB negative patients (n=12), CP-GEP identified five patients (41. 7%) as being Low Risk for nodal metastasis. Overall, the potential SLNB reduction rate in this cohort was 29.4% while having a negative predictive value of 100%.

Conclusions

The CP-GEP (Merlin Assay) model is a non-invasive and validated tool that can be used to identify patients with a primary cutaneous melanoma (pT1 b-pT3) who are at low risk for nodal metastasis and therefore could safely forgo SLNB. Also, during the current COVID-19 pandemic, the CP-GEP model could be a promising tool to deselect patients for elective surgery (Figure).

Background

Patients with high-risk stage III melanoma are currently eligible for systemic adjuvant treatment. However, half of the melanoma patients presenting with disease recurrence were initially diagnosed with stage I-II melanoma. To identify patients at high risk for disease relapse in an early stage, new diagnostic tools are in development. One of these potential diagnostic tools is the CP-GEP model, combining clinicopathologic variables and gene expression measurements. The CP-GEP model was shown to be able to identify melanoma patients at high risk for disease relapse in stage IIA, with a five-year relapse-free survival (5y RFS) of 56%, compared to a 5y RFS of 78% in CP-GEP Low Risk patients. Since the CP-GEP model was developed in a US cohort, validation in a European cohort is warranted. This is the first time the CP-GEP model was used in Europe to identify stage II melanoma patients at high risk for disease relapse.

Methods

This study included patients with cutaneous melanoma patients aged ≥18 years who underwent sentinel lymph node biopsy (SLNB) at the Erasmus MC Cancer Institute (The Netherlands) and Sahlgrenska University Hospital (Sweden) between January 2006 and December 2017. The CP-GEP model combines clinicopathologic features (age and Breslow thickness) with the expression of eight target genes (ITGB3, PLAT, SERPINE2, GDF15, TGFBR1, LOXL4, CXCL8 and MLANA) in the primary tumor, that has already been excised. Patients were stratified according to their risk of relapse: CP-GEP High Risk or CP-GEP Low Risk, using a predefined cut-off value. The primary clinical endpoint of this study was 5yRFS.

Results

In total, 656 stage I-III patients were included in the study. Patients had a median age of 58 years (interquartile range [IQR] 47-69) and the median Breslow thickness was 1.9 mm (IQR 1.3-3.3). In the majority of patients who underwent SLNB, no SLN metastasis was found (i.e. stage I-II melanoma, n=535). Among all stage II patients (n=263), 5y RFS was 73% (95% CI: 67-78). CP-GEP stratification of these stage II patients resulted in a 5y RFS of 87% (95% CI: 76-93, CP-GEP Low Risk, n=72) versus 67% (95% CI: 60-74, CP-GEP High Risk, n=191) (HR 2.82, p<0.004). In comparison, 5y RFS in patients with nodal metastasis (stage III melanoma patients) was 53% (95% CI: 43-61).

Conclusions

The CP-GEP model is a non-invasive tool that can adequately identify stage II cutaneous melanoma patients at high risk for disease relapse within five years, as demonstrated in this European cohort. These results indicate the possible added value of using the CP-GEP model in current clinical practice. CP-GEP High Risk patients may benefit from therapeutic interventions or enhanced surveillance. e.e.a.p.m

Abstract

The management of primary cutaneous melanoma (PCM) faces new challenges during the COVID-19 pandemic. National guidelines aiming to optimize medical resource usage have led to delays in elective surgical procedures such as the sentinel lymph node (SLN) biopsy, which causes stress and anxiety in patients. We recently reported on the development of a model which combines clinicopathologic variables and a gene expression profile (CP-GEP) to identify patients who may safely forgo SLN biopsy due to their low risk of nodal metastasis. The CP-GEP model combines Breslow thickness and patient age with the expression of eight genes in diagnostic biopsy tissue. Here, we report on the feasibility of running the CP-GEP model – which we refer to as the Merlin Assay – in an independent Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory accredited by the College of American Pathologists (CAP). 50 micron recuts of T1 to T3 diagnostic biopsy tissue were requested from 50 PCM patients who were seen in the fall of 2019. Turnaround time from sample receipt at the laboratory to test reporting was within five working days. 3/50 samples (6%) did not contain sufficient RNA for molecular analysis; 47/50 samples (94%) were tested successfully. Of the 47 patients with Merlin test results, 34/47 (72.3%) underwent SLN biopsy. Of the 34 patients with known SLN status, 13/34 (38.2%) were T1, 13/34 (38.2%) were T2 and 8/34 (23.6%) were T3 patients. 1 of 13 (7.7%) T1, 4 of 13 (30.1%) T2 and 1 of 8 (12.5%) T3 patients were SLN positive. All SLN positive patients were correctly classified as high risk by the Merlin Assay. We conclude that the implementation of the Merlin Assay in clinical practice is feasible as a send-out test and may be used for deselecting low risk PCM patients for SLN biopsy during the ongoing COVID-19 pandemic.

Background:

The sentinel lymph node biopsy (SLNB) procedure has gained importance now that primary cutaneous melanoma (PCM) patients with a positive sentinel lymph node are considered candidates for adjuvant systemic therapy. However, SLNB is an invasive procedure, and approximately 80% of patients lack nodal metastasis. Many SLNB negative patients are exposed to invasive surgery but enjoy no discernible therapeutic benefit. Therefore, there is a need for a non-invasive test to accurately identify PCM patients who may forgo the SLNB procedure due to low risk of nodal metastasis. Previously, a clinicopathological and gene expression profile model (CPGEP model) has been developed to identify PCM patients who can safely forgo SLNB. Moreover, a validation of the CP-GEP model in a European cohort has been reported. Here, we describe the validation of the CP-GEP model in a US cohort.

Methods:

We identified 162 patients who underwent SLNB at the Mayo Clinic or West Virginia University within 90 days of PCM diagnosis. Formalin-fixed paraffin embedded diagnostic PCM biopsy tissue from all patients were analyzed using the CPGEP model. The CP-GEP model combines Breslow thickness and patient age with the expression of eight genes to classify patients as CP-GEP High Risk or CP-GEP Low Risk for nodal metastasis.

Results:

At diagnosis, the median patient age was 56 years (IQR, 41 to 69 years) and the median Breslow thickness was 1.9 mm (IQR, 0.9 to 2.1 mm). 62 of 162 patients {38.2%) presented with Tl melanoma while 58 of 162 patients (35.8%) presented with T2 melanoma. Overall, 19.8% of patients had a positive sentinel lymph node. In patients with stage Tl to T2 melanoma, the CP-GEP model achieved an SLNB reduction rate of 44.2% at a negative predictive value of 98.1%.

Conclusions:

The CP-GEP model is a non-invasive and validated tool that is able to predict nodal metastasis in an US cohort that can be used to identify PCM patients who can safely forego SLNB. The CP-GEP model is a promising tool for patient care, preventing unnecessary surgery in a large group of patients.

Background:

In recent years, adjuvant therapy trials in stage III melanoma have been successful and trials have started with the inclusion of stage IIB/C patients. However, stage IIA melanoma patients are currently not eligible for adjuvant therapy, even though a large part of all melanoma related deaths occur in this patient group. Therefore, a strong clinical need has emerged for diagnostic tools that can identify high-risk patients who currently have no access to adjuvant therapy. Here, we sought to assess the ability of a recently introduced clinicopathologic gene expression model (CP-GEP) (Bellomo et al., JCO Precis Oncol. 2020: in press) to select stage IIA patients at high risk for disease relapse, upon design of a stage-specific operating point.

Methods:

We assessed the prognostic performance of the CP-GEP model in all 141 stage IIA patients from a Mayo Clinic cohort of 837 consecutive melanoma patients who had a sentinel lymph node biopsy (SLNb) performed within 90 days of their diagnosis. The CP-GEP model combines Breslow thickness and patient age, with the expression of 8 genes in the primary tumor. Moreover, it stratifies patients according to their risk of relapse: CP-GEP High Risk or CP-GEP Low Risk, based on an operating point that was specifically developed for stage IIA. This stage-specific operating point was selected to fulfill the following criteria: hazard ratio RFS > 2 with a p-value < 0.05, and risk groups of similar size. The main clinical endpoint was five-year relapse free survival (RFS).

Results:

The CP-GEP High Risk group corresponds to 45% (63/141) of all stage IIA patients and captures 62% (18/29) of the total relapses in this substage. Moreover, CP-GEP High Risk patients relapse more frequently than CP-GEP Low Risk patients (RFS of 56% versus 78%; HR, 2.23; P < 0.05). The prognosis for stage IIA CP-GEP High Risk patients in our cohort is worse than for stage IIC/IIIA patients with reported RFS ranging from 63% to 77%.

Conclusions:

The CP-GEP model can be optimized by designing a stage-specific operating point, to identify a subset of stage IIA patients with an increased risk for disease relapse, not very different from IIC/IIIA patients. Therefore, stage IIA CP-GEP High Risk patients may be considered for inclusion in adjuvant trials. Independent validation studies are ongoing for the newly developed operating point.

Purpose

Greater than 80% of melanoma patients who undergo sentinel lymph node (SLN) biopsy are SLN negative. Our objective was to use molecular markers crucial in the reciprocal and bidirectional interaction between integrins and the tumor microenvironment to distinguish between high-risk patients and patients who can safely forego SLN biopsy. 

Patients and Methods 

Genes with functional roles in melanoma metastasis were discovered by analysis of next-generation sequencing data, case-control studies, analysis of publicly available genomic datasets and a review of the cancer literature. Of 192 candidate biomarkers discovered, 108 were quantified by quantitative PCR in a cohort of 754 consecutive thin and intermediate-thickness melanomas. Outcome of interest was SLN metastasis within 90 days of melanoma diagnosis. Logistic regression with LASSO regularization was applied to clinicopathologic variables and molecular data in a cross-validation training-validation scheme. Three models were built using: only clinicopathologic features (CP); only gene expression profiling (GEP); and both clinicopathologic and gene expression profiling (CP-GEP). 

Results 

128/754 patients (17%) were SLN positive. Expression of genes with roles in extracellular matrix remodeling (glia-derived nexin, growth differentiation factor 15, integrin β3, interleukin 8, lysyl oxidase homolog 4, TGFβ receptor type 1 and tissue-type plasminogen activator) and melanosome function (antigen recognized by T-cells) were associated with SLN metastasis. The predictive ability of a model that only considered CP or GEP variables was outperformed by a model which included molecular variables in combination with the clinicopathologic predictors Breslow depth and patient age. CP-GEP achieved a SLN biopsy reduction rate of 80% for clinical stage T1b melanoma with an NPV >95% across all T stages. 

Conclusion 

A combined model including clinicopathologic and gene expression variables improved the identification of melanoma patients who can safely forgo SLN biopsy due to their less than 5% risk of nodal metastasis.