Sentinel lymph node biopsy is recommended for patients with melanomas of 1- to 4-mm thickness to provide accurate staging. It is also recommended for lesions less than 1 mm with certain high-risk features, such as ulceration, more than 1 mitosis/mm2, or lymphovascular invasion. A 2-cm excision margin is appropriate for melanomas that are 1 mm thick or deeper. Metastasis to regional lymph nodes is the most important prognostic factor in early-stage melanoma and is found in 20% of patients with intermediate-thickness melanomas. Patients with intermediate-thickness melanomas have an average 5-year survival of 70% if lymph nodes are negative but only 45% if positive lymph nodes are present. If a positive sentinel lymph node is found, complete lymphadenectomy is recommended, which improves regional disease control. However, it is not known whether this procedure improves overall survival.
Adjuvant chemotherapy is not of benefit in treating melanomas. Palliative chemotherapy can be used for metastatic melanomas, although immunotherapy or targeted treatments offer improved efficacy and are usually recommended instead for advanced disease.
Whether to recommend adjuvant interferon alfa is guided by lymph node status. Adjuvant interferon alfa is an option for patients with positive lymph nodes and/or melanomas that are 4 mm or more thick. In these high-risk patients who have a 25% to 75% risk of dying of metastatic melanoma, adjuvant interferon alfa improves relapse-free survival, with less clear benefit for overall survival. Adjuvant interferon alfa would only be recommended for this patient if lymph node involvement is present.
A meta-analysis showed an improvement in disease-free and overall survival with adjuvant interferon alfa. However, in one of the largest trials, the improvement in overall survival was lost with more prolonged follow-up. Given the toxicities of interferon alfa, including fatigue, myalgia, fever, depression, and autoimmune disease, participation in clinical trials of newer agents is encouraged as an alternative option. Observation alone is also reasonable.
Because of important staging and prognostic information, as well as guidance for potential additional treatment options obtained from a sentinel lymph node biopsy in patients with intermediate-thickness melanoma, performing no further testing would be inappropriate.