This paper reports a prospective cohort study with a five-year follow-up. This is the second report to describe the analysis of data obtained during follow-up of 28 months. To date, 40 patients diagnosed with early-stage mycosis fungoides (stage IA, n = 20; stage IB, n = 20) have been enrolled. All patients have been treated with a minimum of 58 sessions of psoralen and long-wave ultraviolet radiation, with complete clinical and histological clearance of lesions