Background: Psoralen plus ultraviolet (UV) A (PUVA) is the standard treatment for early stage mycosis fungoides (MF). When 8-methoxypsoralen (8-MOP) is used in PUVA therapy, it often produces intolerance reactions such as nausea, vomiting and headache.
Objectives: To investigate whether 5-methoxypsoralen (5-MOP) is a safe and effective alternative to 8-MOP in PUVA therapy for MF.
Methods: A retrospective database search and chart review was done to identify patients with MF who received PUVA with either 5-MOP or 8-MOP as initial monotherapy at our institution. Between 1990 and 2004, 14 patients [seven men and seven women; mean age 70 years, range 51-82; National Cancer Institute disease stages IA (n = 6) and IB (n = 8)] received 5-MOP, and 24 patients [21 men and three women; mean age 58 years, range 28-89; disease stages IA (n = 11), IB (n = 12) and IIB (n = 1)] received 8-MOP.
Results: Twelve of 14 patients (86%) in the 5-MOP group and 22 of 24 (92%) in the 8-MOP group had a complete response to PUVA. These two subgroups of complete responders did not differ significantly in terms of PUVA therapy duration, number of treatments or cumulative UVA dose. They also did not differ significantly in terms of relapse-free rate [8% (one of 12) vs. 23% (five of 22)] or time to relapse [17 months (range 4-31) vs. 14 months (range 4-33)]. Moreover, PUVA maintenance therapy with either 5-MOP or 8-MOP in a subset of patients [26% (nine of 34)] did not affect long-term relapse-free status either.
Conclusions: 5-MOP and 8-MOP have comparable therapeutic efficacy when used in PUVA therapy for MF.