Sentinel Lymph Node Biopsy in Melanoma: Standard of Care, Staging, and Emerging Risk Stratification

Conclusions

• Sentinel lymph node biopsy remains the best current method for staging clinically node-negative melanoma and provides major prognostic information that improves risk stratification.
• The procedure is generally low morbidity, with high mapping success and mostly short-term complications that are usually manageable with wound care or oral antibiotics.
• SLNB may improve melanoma-specific survival in intermediate-thickness melanoma, but it does not appear to benefit thick melanoma in the same way.
• For patients with a positive sentinel node, routine immediate complete lymph node dissection is no longer necessary because ultrasound surveillance achieves similar melanoma-specific survival.
• The size of the sentinel node metastasis matters prognostically, with deposits above about 0.3 mm indicating worse outcomes and helping refine stage IIIA risk.
• Most patients who undergo SLNB are node-negative and therefore do not directly benefit therapeutically, creating a need for better patient selection.
• Gene-expression profiling such as CP-GEP may help identify low-risk patients who can safely avoid SLNB and high-risk patients who should be offered it, but prospective validation is still needed.
• Some patients who are technically T1a can still harbor occult nodal disease and later present with advanced stage, suggesting that biology and not thickness alone should guide decisions in selected cases.
• Adjuvant immunotherapy benefits higher-risk stage III patients more than low-volume stage IIIA patients, where toxicity often outweighs benefit.
• Because adjuvant trials and surveillance strategies were largely built around prior SLNB, the biopsy still plays a central role in guiding downstream management and follow-up.