Surgical procedures in melanoma in 2020: recommended deep and lateral margins, indications for sentinel lymph node biopsy, and complete lymph node dissection.

INTRODUCTION Surgery is the main treatment for cutaneous melanoma including the primary melanoma as well as lymph node metastases. The recommended margins have changed over time. Similarly, indications for sentinel lymph node biopsy and complete lymph node dissection are constantly evolving as long as knowledge on the biological behavior of melanomas increases. EVIDENCE ACQUISITION The current guidelines and the most relevant literature was reviewed to provide an update on the existing recommendations for surgical management of melanoma. EVIDENCE SYNTHESIS Wide excision margins are evidenced-based but not for all situations. Melanoma in situ requires 0.5-1 cm with increasing evidence for 1 cm particularly those presenting on the head and in the setting of chronic sun damage. Invasive melanomas need 1-2 cm margins, 2 cm for tumors thicker than 2 mm and some large tumors with >1-2 mm thickness and with a lentiginous growth pattern. Lentigo maligna, subungual melanoma, and acral lentiginous melanoma require surgical techniques with complete circumferential peripheral margin assessment. Sentinel lymph node biopsy provides relevant information for melanoma staging. Therefore, it is consistently recommended for melanomas >1-4 mm and highly recommended for melanomas >4 mm, >0.8-1.0 mm or ≤0.8 mm with additional risk factors. Complete lymph node dissection has high morbidity and no impact on survival and is restricted to regional control for clinically detected metastasis. CONCLUSIONS Although the trend is to reduce progressively the recommended surgical margins, further evidence is needed to clarify its role in patients' survival. Sentinel lymph node biopsy is important for establishing a prognosis especially upon considering adjuvant therapy; complete lymph node dissection is only relevant for regional disease control.