The optimal duration of treatment with low-dose interferon alfa (LDI) in patients with clinically lymph node–negative melanoma remains to be determined. The phase III DeCOG trial evaluated if there was any benefit from extending the treatment duration LDI from 18 to 60 months in patients with intermediate or high-risk primary melanoma.

The study conducted in Germany and Austria involved 850 patients with resected cutaneous melanoma of at least 1.5mm tumour thickness, who had to be clinically lymph node–negative. They were randomised to receive 3 MU alfa interferon 2a three times a week subcutaneously for either 18 months (arm A) or 60 months (arm B).

Overall, 840 patients were eligible for evaluation after a median follow-up of 4.3 years and sentinel node biopsy was performed in 635 patients (75.6%), with a positivity rate of 18.0% in arm A and 17.5% in arm B. There were no significant differences between the arms in the following measures:

• Relapse-free survival (arm A, 75.6% vs. arm B, 72.6%; hazard ratio, 1.05; 95% CI, 0.80 to 1.39, p = 0.72).

• Distant-metastasis–free survival (81.9% vs. 79.7%, 1.10; 0.80 to 1.52, p = 0.56).

• Overall survival (85.9% vs. 84.9%, 1.03; 0.71 to 1.50, p = 0.86).

The researchers conclude that “a prolongation of conventional LDI therapy from 18 to 60 months showed no clinical benefit in patients with intermediate and high-risk primary melanoma.”