Long-term survival benefit after adjuvant treatment of cutaneous melanoma with dacarbazine and low dose natural interferon alpha:: A controlled, randomised multicentre trial

In a prospective, controlled, randomised, multicentre study 252 patients with totally resected cutaneous melanoma ( 248 in stage II - III and 4 in stage IV) were either treated with two doses of dacarbazine ( DTIC) followed by a 6-month treatment with 3 MU thrice weekly of highly purified natural interferon-alpha ( n = 128; arm A) or received no adjuvant treatment ( n = 124; arm B). Treatment was well tolerated. After a median follow-up of 8.5 years ITT analysis showed that the difference in survival was statistically significant with respect to melanoma-related deaths ( HR = 0.65, CI = 0.46 - 0.97, p = 0.022) and close to significance with respect to overall survival ( HR 0.71, CI 0.49 - 1.00, p = 0.052). The risk reduction of melanoma-associated death, calculated by Cox proportional hazards modelling, after adjusting for identified predictive variables, was almost 50% ( p = 0.002). The overall efficacy of the treatment appeared to be mainly attributable to effects observed in patients with deep and/or metastasizing tumours ( HR 0.60, CI 0.40 - 0.90, p = 0.013).