Immunotherapy of metastatic melanoma with interferon-alpha and interleukin-2: pattern of progression in responders and patients with stable disease with or without resection of residual lesions.

This evaluation was performed in melanoma patients after successful immunotherapy to describe the pattern of relapse. 63 patients received interferon (IFN)-alpha and high-dose interleukin (IL)-2, resulting in three complete responses (CR), 13 partial responses (PR), three mixed responses (MR) and 17 stable diseases (SD). Median duration of response was 7 months (range 3-28) without surgery. Most relapses occurred at pre-existing sites. Duration of CR was 14-37+ months. In 11 patients, residual tumour lesions were resected. Interestingly, histology revealed almost complete tumour regression in 6 patients, including 2 of 4 with SD. 5 of these 11 patients have relapsed so far, 6 patients are still free of disease with a median of 17 months (range 8-34). Following relapse, 4 of 6 patients responded to retreatment with the identical IFN alpha/IL-2 protocol. The authors conclude that initial disease progression is mostly at previous sites of disease. Resection of residual lesions may offer a chance for extended disease-free survival similar to patients with CR to immunotherapy. Retreatment of relapsing patients is favourable.