The role of adjuvant therapy in melanoma management.

Abstract

Adequate wide excision of a primary cutaneous melanoma is associated with a 10-year cure rate of 85% when the tumor's depth is less than 1.5 mm (American Joint Committee on Cancer [AJCC] Stage I). However, 50% of patients with deep (> 4 mm) primary melanomas, 60-85% of those with regional lymph node metastases (AJCC Stage III), and 95% of those with metastases to distant sites (AJCC Stage IV) will experience recurrence, which is associated with a dismal prognosis. Adjuvant therapy of melanoma assumes that treatment will be more effective when the tumor burden is small. In the 1970s and 1980s, randomized trials tested the efficacy of chemotherapy, nonspecific immunotherapy, levamisole, and regional perfusion therapy in patients with AJCC Stage II and III melanoma. Dacarbazine (DTIC) alone or in combination with other chemotherapeutic drugs or with nonspecific immunotherapy did not significantly improve disease free or overall survival. Of the four levamisole trials, only the study conducted by the National Cancer Institute of Canada revealed a reduction in recurrence and mortality; however, this reduction was not significant by multivariate analysis. The value of regional perfusion therapy following resection of high risk extremity melanomas is currently being determined by multiinstitutional studies conducted by the World Health Organization and the North American Perfusion Group. Multi-institutional trials also are examining the adjuvant role of interferon-alpha in patients with deep (> 3 mm) primary melanomas or positive regional lymph nodes; results should reveal its optimum dose and duration of treatment (3 x 10(6) U for > or = 2 years versus 10 x 10(6) U/m2 for 1 year, subcutaneously 3 times a week) and its impact on survival. A randomized trial of interferon-gamma undertaken by the Southwest Oncology Group was discontinued after interim analysis indicated an adverse effect. Phase II trials indicate that active specific immunotherapy can alter the natural course of AJCC Stage III and IV melanoma following surgical resection of nodal or distant metastases. Upcoming results of Phase III trials will establish the role of active specific immunotherapy for adjuvant treatment of patients with resected AJCC Stage III and IV melanoma.