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Melanoma

Circulating Tumor DNA for Minimal Residual Disease Detection & Molecular Profiling

Clinical Overview

Cutaneous melanoma represents one of the most well-studied applications of ctDNA testing in solid tumors. While early-stage melanoma has excellent prognosis following surgical resection, approximately 20-30% of patients with stage II-III disease experience recurrence. Molecular profiling has revealed actionable BRAF mutations in approximately 50% of patients, enabling targeted therapy selection between BRAF/MEK inhibitor combinations and immunotherapy approaches.

Recent advances in immunotherapy with anti-PD-1 antibodies and targeted therapy with BRAF/MEK inhibitor combinations have transformed melanoma treatment. However, determining which patients require adjuvant therapy after surgical resection, and which patients will benefit from treatment intensification, remains a clinical challenge. Circulating tumor DNA has demonstrated prognostic value in identifying high-risk patients with molecular evidence of residual disease.

Clinical Impact: Multiple prospective studies have established ctDNA as a prognostic biomarker in melanoma, with hazard ratios ranging from 3.5 to 38 for recurrence depending on disease stage and testing timepoint. Lead times of 5.5-8.7 months before radiographic progression enable potential early intervention, though prospective trials testing whether ctDNA-guided treatment improves survival are ongoing.

Understanding ctDNA Testing Methodology

Clinical Decision Points for Melanoma

When to Use Each Approach

Clinical Scenario Recommended Approach Rationale
Post-surgical MRD detection (Stage IIB-IV) Tumor-informed Maximum sensitivity needed; uses baseline profiling from surgery
Adjuvant therapy decision Tumor-informed Clinical trials used baseline-informed approach for risk stratification
BRAF V600E genotyping Either approach Can be detected with or without baseline profiling
Treatment resistance monitoring Either approach Can track emerging mutations with or without baseline
Surveillance (years 0-2) Tumor-informed Highest sensitivity using baseline mutation tracking

LIQOMICS Testing Solutions for Melanoma

CancerVista offers tumor-informed ctDNA testing for melanoma enabling MRD detection after surgery and monitoring during systemic therapy.

Key Features:

  • Baseline profiling from tissue biopsy or plasma sample
  • Ultra-high sensitivity for MRD detection
  • Tracks patient-specific mutations for specific and precise MRD quantification
  • Enables ctDNA-guided therapy decisions
  • Allows early relapse detection during surveillance

Learn More About CancerVista →

MRD Detection Clinical Utility

Prognostic Value in Resected Melanoma

Multiple prospective studies have demonstrated strong prognostic value of ctDNA detection after surgical resection in stage II-IV melanoma patients. Detection of molecular residual disease identifies patients at dramatically higher risk of recurrence.

Prospective ctDNA Analyses in Resected Melanoma

Pooled evidence from prospective studies in resected stage IIB-IV melanoma:

ctDNA Detection Rates by Stage:

  • Stage IIB-IIC: 10-15% ctDNA-positive
  • Stage IIIA-IIIB: 20-25% ctDNA-positive
  • Stage IIIC-IV: 35-45% ctDNA-positive

Recurrence Risk by ctDNA Status:

  • Hazard Ratio: 1.85 for relapse-free survival (95% CI 1.39-2.46, p<0.0001)
  • Stage-dependent HR: HR 3.5-6.2 depending on stage
  • Clinical Significance: ctDNA status remained prognostic independent of stage

Sensitivity and Specificity for MRD Detection

Test Performance Characteristics:

  • Sensitivity for future recurrence: 77-92% depending on stage and method
  • Specificity: 94-98% (low false-positive rate)
  • Positive Predictive Value: 65-80% depending on disease stage
  • Negative Predictive Value: 85-95% (8-15% of ctDNA-negative patients still recur)

Lead Time Before Imaging Detection

Early Detection Performance:

  • Median Lead Time: 5.5-8.7 months before radiographic recurrence (range 1-24 months)
  • Clinical Implication: Molecular detection precedes clinical/imaging progression
  • Intervention Window: Sufficient time for treatment modification or clinical trial enrollment
  • Surveillance Frequency: Testing every 3 months during first 2 years captures most relapses

Prognostic Value by Testing Timepoint

Post-Surgical Timepoint (4-8 weeks)

Immediate Post-Surgical Assessment:

  • Hazard Ratio: 6.8-11.5 for recurrence if ctDNA-positive
  • Detection Rate: 15-25% of patients depending on stage
  • Clinical Use: Identifies highest-risk patients for adjuvant therapy consideration

End-of-Treatment Timepoint

After Adjuvant Therapy Completion:

  • Hazard Ratio: 12-38 for recurrence if ctDNA-positive
  • Detection Rate: 5-10% of patients who completed adjuvant therapy
  • Clinical Significance: Extremely high-risk population requiring intensification

Longitudinal Monitoring During Surveillance

Serial Testing Performance:

  • Conversion from negative to positive: HR 15-25 for recurrence
  • Persistently negative: 90-95% remain recurrence-free at 2 years
  • Optimal Frequency: Every 3 months during years 1-2, then every 6 months years 3-5

Comparison with Traditional Risk Factors

ctDNA vs Clinical Staging:

Risk Factor Hazard Ratio for Recurrence Independent Prognostic Value
ctDNA positivity (post-surgical) 6.8-11.5 Yes - independent of stage
Stage IIIC vs IIIA 2.5-3.2 Yes
Ulceration present 1.8-2.1 Yes
Breslow thickness >4mm 2.0-2.5 Yes
Tumor mutational burden (high) 1.2-1.5 No - not independent of ctDNA

Key Finding: ctDNA status is the strongest prognostic factor, outperforming traditional clinical and molecular biomarkers.

Clinical Application: Post-surgical ctDNA testing identifies patients at high risk of recurrence who may benefit from adjuvant therapy or treatment intensification. The 5.5-8.7 month lead time before radiographic progression provides a window for early intervention, though prospective trials are ongoing to determine whether ctDNA-guided treatment improves survival outcomes.

Genotyping for Targeted Therapy Selection

Beyond MRD detection, ctDNA enables non-invasive genotyping for actionable mutations guiding treatment selection in melanoma. Molecular profiling has become essential for distinguishing patients eligible for targeted therapy versus immunotherapy approaches.

BRAF V600 Mutations: BRAF/MEK Inhibitor Combinations

Clinical Context and Treatment Options

Prevalence and Detection:

  • Frequency: 50% of cutaneous melanoma (V600E most common, V600K 15-20%)
  • ctDNA-Tissue Concordance: >95% for BRAF V600E detection
  • Clinical Advantage: Non-invasive testing enables rapid treatment selection

BRAF/MEK Inhibitor Combination Therapy:

  • First-line regimens: Dabrafenib + trametinib, encorafenib + binimetinib, vemurafenib + cobimetinib
  • Response Rate: 60-70% objective response rate
  • Median PFS: 11-15 months with combination therapy
  • Median OS: 25-33 months depending on regimen

Adjuvant Setting: COMBI-AD Trial Results

Phase III RCT in Resected Stage III BRAF-Mutant Melanoma:

  • Treatment: Dabrafenib + trametinib vs placebo for 12 months
  • 5-Year Relapse-Free Survival: 52% vs 36% (HR 0.51, 95% CI 0.42-0.61)
  • 5-Year Distant Metastasis-Free Survival: 65% vs 54% (HR 0.55, 95% CI 0.44-0.70)
  • Overall Survival (final analysis, 8-year follow-up): 71% vs 65% (HR 0.80, 95% CI 0.62-1.01; not statistically significant)
  • Clinical Significance: Statistically significant improvement in relapse-free survival; OS trend favoring combination but not significant

COMBI-AD ctDNA Biomarker Validation (Lancet Oncology 2025)

First Clinical Validation of ctDNA in a Phase III Adjuvant Melanoma Trial:

  • Method: Analytically validated droplet digital PCR (ddPCR) for BRAF V600E/K ctDNA
  • Baseline Detection: ctDNA detectable in 13% (79/597) of baseline samples
  • Prognostic Impact: ~80% of patients with detectable baseline ctDNA experienced recurrence
  • Recurrence Speed: Disease returned more than 4 times faster in ctDNA-positive vs ctDNA-negative patients
  • Longitudinal Kinetics: Patients with adverse ctDNA kinetics (molecular relapse or persistently positive) had median RFS of 8.3 and 5.3 months, respectively, vs 19.3 months for favorable kinetics (p<0.0001)
  • During Follow-up: Nearly 100% of patients who became ctDNA-positive during follow-up experienced recurrence
  • Clinical Implication: Validates ctDNA monitoring for early detection of recurrence during and after adjuvant targeted therapy

CheckMate 915 ctDNA Biomarker Analysis (2025)

Largest ctDNA Assessment in Adjuvant Immunotherapy for Melanoma:

  • Population: Resected stage IIIB-D/IV melanoma treated with adjuvant nivolumab or nivolumab + ipilimumab
  • Baseline ctDNA Positivity: 16.2% of patients
  • Prognostic Value: ctDNA positivity associated with higher recurrence risk (HR 1.97, 95% CI 1.57-2.46)
  • Specificity: 87% for predicting recurrence
  • Sensitivity: 39% (modest, reflecting low tumor shedding in resected disease)
  • Multi-Biomarker Enhancement: Combining ctDNA with TMB and IFN-gamma RNA signature was more predictive than ctDNA alone

NRAS Mutations: Limited Targeted Options

Clinical Characteristics:

  • Frequency: 28% of cutaneous melanoma
  • Common sites: Q61R, Q61K most frequent
  • Mutually exclusive: NRAS mutations rarely co-occur with BRAF
  • Targeted therapy: Binimetinib (MEK inhibitor) shows modest benefit
  • Response Rate: 15-20% with MEK inhibitor monotherapy
  • Standard approach: Immunotherapy preferred for NRAS-mutant melanoma

c-KIT Mutations: Rare but Actionable

Clinical Context:

  • Frequency: <5% overall, enriched in acral (15-20%) and mucosal (20-25%) melanoma
  • Targeted therapy: Imatinib, dasatinib
  • Response Rate: 20-30% with imatinib in c-KIT mutant/amplified tumors
  • Testing indication: Acral, mucosal, or chronically sun-damaged melanomas
  • ctDNA utility: Non-invasive detection avoids repeat biopsy in advanced disease

Neoadjuvant Immunotherapy: NADINA Trial

Phase III RCT: Neoadjuvant Nivolumab + Ipilimumab vs Adjuvant Nivolumab (Stage III Melanoma):

  • Design: Multicenter, randomized phase III trial in macroscopic resectable stage III melanoma
  • 12-Month Event-Free Survival: 85.2% (neoadjuvant) vs 61.7% (adjuvant)
  • 24-Month Event-Free Survival: 77.3% (neoadjuvant) vs 55.7% (adjuvant)
  • Hazard Ratio for EFS: 0.40 (95% CI 0.28-0.57, p<0.001) - 60% risk reduction
  • 24-Month DMFS: 82.8% (neoadjuvant) vs 63.9% (adjuvant)
  • Major Pathologic Response: 59.0% achieved MPR, allowing some patients to avoid adjuvant therapy entirely
  • ctDNA Relevance: Establishes neoadjuvant immunotherapy as a new paradigm; ctDNA monitoring may further refine patient selection and response assessment in this setting

PD-L1 Expression and TMB: Immunotherapy Selection

Biomarkers for Checkpoint Inhibitor Therapy

PD-L1 Expression:

  • Testing method: Immunohistochemistry on tissue (not ctDNA)
  • Adjuvant pembrolizumab: HR 0.57 for recurrence-free survival (KEYNOTE-054)
  • Clinical note: Benefit seen regardless of PD-L1 status in adjuvant setting

Tumor Mutational Burden (TMB):

  • High TMB (>10 mutations/Mb): 60-70% of melanomas
  • Association: Higher TMB correlates with improved immunotherapy response
  • Response Rate: 40-50% in TMB-high vs 15-25% in TMB-low
  • ctDNA assessment: TMB can be estimated from plasma ctDNA panels
  • Limitation: TMB alone insufficient for treatment selection decisions

Comprehensive Genotyping Strategy

Recommended Testing Algorithm:

  1. All advanced melanoma patients: BRAF V600, NRAS mutation testing at baseline
  2. Acral/mucosal/CSD melanoma: Add c-KIT mutation testing
  3. BRAF V600E-positive:
    • Adjuvant: Consider dabrafenib + trametinib based on stage and risk
    • Metastatic: BRAF/MEK combination vs immunotherapy based on disease burden
  4. BRAF wild-type: Immunotherapy (anti-PD-1 ± anti-CTLA-4) first-line
  5. Resistance monitoring: Repeat ctDNA genotyping at progression to identify resistance mechanisms

Treatment Selection by Molecular Profile

Molecular Profile Prevalence Preferred Treatment Response Rate
BRAF V600E/K 50% BRAF/MEK inhibitor combination 60-70%
NRAS mutant 28% Anti-PD-1 immunotherapy 40-50%
c-KIT mutant (acral/mucosal) 15-25% Imatinib or immunotherapy 20-30%
BRAF/NRAS wild-type 20% Anti-PD-1 immunotherapy 40-45%
TMB-high (any genotype) 60-70% Immunotherapy preferred 40-50%

Clinical Summary and Practice Considerations

Melanoma ctDNA testing demonstrates clinical utility with:

  1. Strong Prognostic Value: HR 3.5-38 for recurrence depending on timepoint and stage
  2. High Sensitivity and Specificity: 77-92% sensitivity, 94-98% specificity for MRD detection
  3. Meaningful Lead Time: 5.5-8.7 months before radiographic progression
  4. Actionable Genotyping: BRAF V600 (50%), NRAS (28%), c-KIT (rare) guide targeted therapy
  5. Clinical Validation: COMBI-AD and CheckMate 915 ctDNA biomarker analyses (both published 2025) provide phase III-level validation of ctDNA prognostic value in adjuvant setting
  6. Neoadjuvant Paradigm: NADINA trial (HR 0.40 for EFS) establishes neoadjuvant immunotherapy, with ctDNA monitoring as an emerging tool for response assessment
  7. Evidence Gap: Prospective trials testing whether ctDNA-guided treatment selection improves survival are ongoing

Evidence-Based Application Strategy

Recommended Clinical Pathway:

  1. Stage IIB-IV melanoma: Consider baseline ctDNA 4-8 weeks post-surgery for risk stratification
  2. BRAF genotyping: All advanced melanoma patients for treatment selection
  3. High-risk patients: Serial ctDNA monitoring every 3 months during years 0-2
  4. ctDNA-positive during surveillance: Confirm with imaging, consider treatment intensification or clinical trial
  5. Resistance monitoring: Repeat genotyping at progression on targeted therapy

Clinical Perspective: Melanoma represents one of the most extensively studied applications of ctDNA testing, with strong prognostic data demonstrating risk stratification capability. The technology provides valuable molecular information for treatment selection through BRAF genotyping and identifies high-risk patients through MRD detection. While the prognostic value is well-established, prospective interventional trials are needed to demonstrate that ctDNA-guided treatment decisions improve patient outcomes. Current use should focus on genotyping for treatment selection and risk stratification in stage IIB-IV disease, ideally within clinical trials or research protocols.

References

  1. Lee RJ, Gremel G, Marshall A, et al. Circulating tumor DNA predicts survival in patients with resected high-risk stage II/III melanoma. Ann Oncol 2018;29:490-496.
  2. Tan L, Sandhu S, Lee RJ, et al. Prediction and monitoring of relapse in stage III melanoma using circulating tumor DNA. Ann Oncol 2019;30:804-814.
  3. Syeda MM, Wiggins JM, Corless BC, et al. Circulating tumour DNA in patients with advanced melanoma treated with dabrafenib or dabrafenib plus trametinib: a clinical validation study. Lancet Oncol 2021;22:370-380.
  4. Marsavela G, McEvoy AC, Pereira MR, et al. Circulating tumor DNA predicts outcome from first-, but not second-line treatment and identifies melanoma patients who may benefit from combination immunotherapy. Clin Cancer Res 2020;26:5926-5933.
  5. Long GV, Hauschild A, Santinami M, et al. Adjuvant dabrafenib plus trametinib in stage III BRAF-mutated melanoma. N Engl J Med 2017;377:1813-1823.
  6. Dummer R, Hauschild A, Santinami M, et al. Five-year analysis of adjuvant dabrafenib plus trametinib in stage III melanoma. N Engl J Med 2020;383:1139-1148.
  7. Ascierto PA, McArthur GA, Dréno B, et al. Cobimetinib combined with vemurafenib in advanced BRAF(V600)-mutant melanoma (coBRIM): updated efficacy results from a randomised, double-blind, phase 3 trial. Lancet Oncol 2016;17:1248-1260.
  8. Eggermont AMM, Blank CU, Mandala M, et al. Adjuvant pembrolizumab versus placebo in resected stage III melanoma. N Engl J Med 2018;378:1789-1801.
  9. Weber J, Mandala M, Del Vecchio M, et al. Adjuvant nivolumab versus ipilimumab in resected stage III or IV melanoma. N Engl J Med 2017;377:1824-1835.
  10. Gide TN, Wilmott JS, Scolyer RA, et al. Primary and acquired resistance to immune checkpoint inhibitors in metastatic melanoma. Clin Cancer Res 2018;24:1260-1270.
  11. Lee JH, Long GV, Menzies AM, et al. Association between circulating tumor DNA and pseudoprogression in patients with metastatic melanoma treated with anti-programmed cell death 1 antibodies. JAMA Oncol 2018;4:717-721.
  12. Bratman SV, Yang SYC, Iafolla MAJ, et al. Personalized circulating tumor DNA analysis as a predictive biomarker in solid tumor patients treated with pembrolizumab. Nat Cancer 2020;1:873-881.
  13. Cabel L, Proudhon C, Romano E, et al. Clinical potential of circulating tumour DNA in patients receiving anticancer immunotherapy. Nat Rev Clin Oncol 2018;15:639-650.
  14. Khagi Y, Goodman AM, Daniels GA, et al. Hypermutated circulating tumor DNA: correlation with response to checkpoint inhibitor-based immunotherapy. Clin Cancer Res 2017;23:5729-5736.
  15. Herbreteau G, Vallée A, Knol AC, et al. Quantitative monitoring of circulating tumor DNA predicts response of cutaneous metastatic melanoma to anti-PD1 immunotherapy. Oncotarget 2018;9:25265-25276.
  16. McEvoy AC, Warburton L, Al-Ogaili Z, et al. Correlation between circulating tumour DNA and metabolic tumour burden in metastatic melanoma patients. BMC Cancer 2018;18:726.
  17. Long GV, Hauschild A, Santinami M, et al. Final results for adjuvant dabrafenib plus trametinib in stage III melanoma. N Engl J Med 2024;391:1709-1720.
  18. Long GV, Carlino MS, Saw RPM, et al. Clinical validation of droplet digital PCR assays in detecting BRAFV600-mutant circulating tumour DNA as a prognostic biomarker in patients with resected stage III melanoma receiving adjuvant therapy (COMBI-AD). Lancet Oncol 2025. doi:10.1016/S1470-2045(25)00139-1.
  19. Weber JS, Schadendorf D, Del Vecchio M, et al. Pretreatment and on-treatment ctDNA and tissue biomarkers predict recurrence in patients with stage IIIB-D/IV melanoma treated with adjuvant immunotherapy: CheckMate 915. J Immunother Cancer 2025;13:e011697.
  20. Blank CU, Reijers ILM, Dimitriou F, et al. Neoadjuvant nivolumab and ipilimumab in resectable stage III melanoma (NADINA). N Engl J Med 2024;391:1537-1548.

Evidence summary current through April 2026 | Version 3.0

This educational resource incorporates the latest clinical trial data for ctDNA testing in melanoma

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