A 48-year-old woman with a history of cutaneous melanoma (Breslow thickness 1.8 mm, Clark level IV, no ulceration) underwent wide local excision 3 years ago. She now presents with a 2 cm firm nodule in the left axilla. Fine-needle aspiration cytology and imaging confirm metastatic melanoma (Stage IIIC). She is BRAF V600E mutation-positive. After lymphadenectomy, what is the drug of choice for adjuvant therapy to reduce the risk of distant recurrence?

Explanation

## Adjuvant Therapy for Resected Stage III Melanoma with Nodal Metastasis **Key Point:** Nivolumab (anti-PD-1 checkpoint inhibitor) is the standard adjuvant therapy for resected Stage IIIC melanoma, regardless of BRAF mutation status. BRAF inhibitor combinations are reserved for metastatic (Stage IV) disease, not adjuvant therapy. ### Why NOT BRAF Inhibitors in the Adjuvant Setting? Although the patient is BRAF V600E-positive, adjuvant therapy guidelines prioritize checkpoint inhibitors over targeted therapy: 1. **Checkpoint inhibitors** (nivolumab, pembrolizumab) have demonstrated superior recurrence-free survival (RFS) in resected Stage III disease (CheckMate 238, KEYNOTE-054). 2. **BRAF inhibitor combinations** (vemurafenib + cobimetinib, dabrafenib + trametinib) are indicated for metastatic (Stage IV) disease, where they improve progression-free survival (PFS) and OS. 3. **No adjuvant benefit** has been proven for BRAF inhibitors in resected disease; checkpoint inhibitors are preferred. ### Clinical Decision Tree for Melanoma Treatment ```mermaid flowchart TD A[Melanoma Diagnosis]:::outcome --> B{Stage?}:::decision B -->|Stage I–II| C[Surgery alone]:::action B -->|Stage III resected| D[Adjuvant Immunotherapy]:::action B -->|Stage IV metastatic| E{BRAF mutant?}:::decision D --> F[Nivolumab or Pembrolizumab]:::action E -->|Yes| G[BRAF + MEK inhibitor]:::action E -->|Yes, alternative| H[Checkpoint inhibitor]:::action E -->|No| H G --> I[Improved PFS & OS in metastatic disease]:::outcome H --> J[Improved OS in metastatic disease]:::outcome F --> K[Improved RFS & OS in resected Stage III]:::outcome ``` ### Adjuvant vs. Metastatic Treatment Paradigm | Setting | Stage | Drug of Choice | Mechanism | Key Trial | |---------|-------|-----------------|-----------|----------| | **Adjuvant** | III (resected) | Nivolumab or Pembrolizumab | Anti-PD-1 | CheckMate 238, KEYNOTE-054 | | **Metastatic** | IV, BRAF-mutant | Dabrafenib + Trametinib or Vemurafenib + Cobimetinib | BRAF/MEK inhibitor | COMBI-v, coBRIM | | **Metastatic** | IV, BRAF wild-type | Nivolumab or Pembrolizumab | Anti-PD-1 | CheckMate 066, KEYNOTE-006 | | **Metastatic** | IV, any BRAF | Ipilimumab + Nivolumab | CTLA-4 + PD-1 | CheckMate 067 | **High-Yield:** The presence of BRAF mutation does NOT change adjuvant therapy choice. Checkpoint inhibitors are superior for resected disease; BRAF inhibitors are for metastatic disease only. **Clinical Pearl:** A common exam trap is offering BRAF inhibitors for adjuvant therapy in BRAF-mutant melanoma. Remember: BRAF inhibitors are for metastatic disease; checkpoint inhibitors are for resected Stage III disease. **Mnemonic:** **STAGE-DRIVEN THERAPY** - **Stage III (resected):** Checkpoint inhibitors (Nivolumab, Pembrolizumab) - **Stage IV (metastatic, BRAF-mutant):** BRAF + MEK inhibitors (Vemurafenib + Cobimetinib, Dabrafenib + Trametinib) - **Stage IV (metastatic, BRAF wild-type):** Checkpoint inhibitors or combination (Ipilimumab + Nivolumab)