Low-Dose Adjuvant Interferon for Stage III Malignant Melanoma

Abstract

The role of interferon as adjuvant therapy in stage III melanoma has recently been questioned. Prospective randomized studies have shown conflicting results regarding the efficacy of adjuvant treatment. The purpose of this study was to examine the use of low-dose adjuvant interferon alpha2-b (IFN) in stage III melanoma patients treated at a single institution. This study was a retrospective analysis of 60 stage III melanoma cases from Wake Forest University treated between 1983 and 1998. Cases were identified via the tumor registry. All patients underwent standard lymphadenectomy after diagnosis. After recovery from surgery patients were offered low-dose IFN (3 million units subcutaneous TIW for 1 month and then 6 million units subcutaneous TIW for 11 months) as adjuvant therapy for stage III melanoma. The patients were followed up jointly by medical and surgical oncology. There were 39 male and 21 female patients with mean age of 60.0 (range 37-89) years. The average number of positive nodes was 3.6 (median = 1) for the treated group and 1.8 (median = 1) for those untreated (P = 0.71). The average tumor thickness was similar between groups: 4.71 versus 4.88 mm for the IFN and observation groups respectively. The IFN group (N = 25) that received low-dose treatment had a median survival of 7.9 years with a 5-year survival rate of 69 per cent. The 35 cases that did not receive interferon had a median survival of 6.5 years and a 5-year survival rate of 52 per cent. These survival rates were not significantly different (P = 0.91). The median disease-free survival for patients who did not receive IFN treatment was 2.4 years and 1.4 years for the treated group (P = 0.19). The data show that there was similar survival for those who did and did not receive the low-dose IFN treatment. Although only large prospective trials can conclusively exclude a small survival time this experience suggests that there is no significant survival advantage to low-dose adjuvant IFN therapy for stage III melanoma patients. Hopefully upcoming cooperative group trials will clarify the potential value of adjuvant IFN in this setting. However, although the toxicity of this regimen was mild we suggest that low-dose adjuvant IFN for stage III melanoma should not be utilized outside the setting of a clinical trial.