Phototherapy as a treatment of early-stage mycosis fungoides and predictive factors for disease recurrence: A 17-year retrospective study

Abstract

Background: Mycosis fungoides is the most common form of cutaneous T-cell lymphoma. Narrowband ultraviolet B and psoralen and ultraviolet A are effective treatment options, but studies of their treatment efficacy and disease relapse remain limited. Objectives: This study aimed (1) to determine the efficacy of narrowband ultraviolet B and psoralen and ultraviolet A as a treatment for early-stage mycosis fungoides and explore the predictive factors for complete remission and (2) to determine the relapse rate and analyze their predictive factors, including the utility of maintenance therapy. Methods: This was a retrospective cohort study consisting of 61 patients with early-stage mycosis fungoides (IA - IB) treated with narrowband ultraviolet B or psoralen and ultraviolet A as the first-line therapy from January 2002 to December 2018 at the Division of Dermatology, Ramathibodi Hospital, Bangkok, Thailand. Cox regression analysis and Kaplan-Meier survival curve were performed for the main outcomes. Results: A complete remission was achieved by 57 (93.5%) patients. The median time to remission was 7.80 ± 0.27 months. Types of phototherapy (narrowband ultraviolet B or psoralen and ultraviolet A), age and gender did not associate with time to remission, while the presence of poikiloderma and higher disease stage led to a longer time to remission. The cumulative incidence of relapse was 50.8%. The median time to relapse was 24.78 ± 5.48 months. In patients receiving phototherapy during the maintenance period, a treatment duration longer than six months was associated with a significantly longer relapse-free interval. Conclusion: Narrow-band-ultraviolet B and psoralen and ultraviolet A are effective treatment options for early-stage mycosis fungoides. Maintenance treatment by phototherapy for at least six months seems to prolong remission.