these are tough decisions, no doubt. He has stage III melanoma because of the one lymph node. Here is the problem. With surgery alone, about 60 % of patients will have their melanoma recurr. Once this happens, survival is poor. Interferon will reduce this recurrence rate by 10-15%. Not much you might say given the year of treatment and the side effects of the drug, but if he is young, I would want to do anything to improve his chances. It is good that he had only one + node instead of several, but he still has a fairly high chance of recurrence without treatment.