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.