A 38-year-old woman from Bangalore undergoes excisional biopsy for a 3.5 mm melanoma on her back with ulceration and 12 mitoses per mm². SLNB shows micrometastatic disease in one sentinel lymph node (1 mm focus of melanoma). What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has Stage III melanoma (Breslow 3.5 mm with ulceration + positive SLNB with micrometastatic disease). The presence of nodal metastases fundamentally changes management from observation to active intervention. ## Staging and Risk Stratification **Key Point:** Positive SLNB indicates Stage III disease and mandates: 1. **Complete regional lymph node dissection (CLND)** of the involved basin 2. **Adjuvant systemic therapy** (checkpoint inhibitors or targeted therapy) **High-Yield:** The combination of high Breslow thickness (3.5 mm), ulceration, and positive SLNB places this patient at very high risk for systemic recurrence. Adjuvant therapy is strongly recommended and has been shown to improve recurrence-free survival (RFS) and overall survival (OS). ## Management Algorithm for Stage III Melanoma ```mermaid flowchart TD A[Positive SLNB<br/>Stage III Melanoma]:::outcome --> B[Complete Regional<br/>Lymph Node Dissection]:::action B --> C{BRAF mutation<br/>status?}:::decision C -->|BRAF V600E/K positive| D[BRAF/MEK inhibitor<br/>or Checkpoint Inhibitor]:::action C -->|BRAF wild-type| E[Checkpoint Inhibitor<br/>Nivolumab or Pembrolizumab]:::action D --> F[Adjuvant therapy<br/>for 1 year]:::action E --> F F --> G[Surveillance imaging<br/>& clinical follow-up]:::action ``` ## Why Complete Lymph Node Dissection Is Necessary | Aspect | Rationale | |--------|----------| | **Staging accuracy** | CLND identifies additional nodal involvement (up to 20–30% of SLNB-positive patients have additional positive nodes) | | **Prognostic information** | Number and size of involved nodes refine Stage III substaging (IIIA, IIIB, IIIC) and guide intensity of adjuvant therapy | | **Local control** | Reduces regional recurrence risk | | **Therapeutic intent** | Removes a known site of metastatic disease | **Clinical Pearl:** The COMBI-AD and CheckMate 238 trials demonstrated that adjuvant BRAF/MEK inhibitors (dabrafenib + trametinib) and checkpoint inhibitors (nivolumab) improve RFS in Stage III melanoma. Adjuvant therapy is now standard of care and should be offered after CLND. ## Why Other Options Are Suboptimal **Observation alone (Option 1):** Leaves known metastatic disease untreated; historically associated with high rates of systemic recurrence and death. No longer acceptable standard of care. **Adjuvant immunotherapy without CLND (Option 2):** While checkpoint inhibitors are effective, CLND provides critical staging information and local control. Both CLND and systemic therapy are recommended. **PET-CT and chemotherapy (Option 3):** Whole-body PET-CT is not standard staging for Stage III melanoma (reserved for Stage IV or symptomatic patients). Systemic chemotherapy (e.g., dacarbazine) is inferior to modern immunotherapy and is rarely used in the adjuvant setting. **Warning:** Do not confuse the role of SLNB (staging only) with CLND (staging + therapeutic). CLND is indicated when SLNB is positive and should be performed before or concurrent with adjuvant systemic therapy decisions.