Potential of narrow-band ultraviolet B to induce sustained durable complete remission off-therapy in patients with stage I mycosis fungoides

Background: Narrow-band ultraviolet B (NB-UVB) is a first-line therapy for stage I mycosis fungoides (MF), with a complete response in 75%-85% of patients. However, data on long-term disease-free survival (DFS) after therapy are scarce. Objective: To assess the long-term DFS after NB-UVB treatment of stage I MF. Methods: We used a historic cohort of all stage I MF patients achieving a complete response with NB-UVB who discontinued treatment before 2011. Age at the beginning of phototherapy, sex, stage, skin phototype, number of treatments, total dose, and the length of DFS was collected. Results: Of the 117 patients who started NB-UVB, 93 patients (80%) had a complete response and 56 (60%) were disease free as of March 2017. In a multivariate analysis, DFS was affected independently by age and disease stage only. DFS was longer for patients <50 years old (124 months) than those ≥50 years old (91 months, P = .01) and longer for stage IA patients (131 months) than stage IB patients (87.6 months, P = .001). Limitations: The study was retrospective in nature. Conclusion: After a single course of NB-UVB, over a half of stage I MF patients achieved >5 years of DFS and were potentially cured. Thus, NB-UVB can be considered a disease-modifying therapy.