Treatment of mycosis fungoides by 308 nm excimer laser: a clinical and histological study in 10 patients.

Background. Mycosis fungoides is a cutaneous T-cell lymphoma. The early stages have a good prognosis but pose therapeutic problems due to chronic disease status and the frequent recurrence of lesions. We performed a retrospective clinical and histological study in 10 patients presenting mycosis fungoides in order to evaluate the efficacy of 308 nm excimer laser in this indication. Methods. Ten patients with mycosis fungoides confirmed by histological examination were included. Treatment by 308 nnn excimer laser was performed on a total of 29 lesions (25 patch-stage, 3 plaques and 1 nodule). After determination of the minimal erythernal dose, sessions were started twice weekly gradually increasing in accordance with tolerability. Clinical follow-up was performed and histological and immunohistological analysis was done, if possible, before and after treatment and at the end of the follow-up. Results. Eighty-six percent of patch-stage or plaque lesions had completely cleared up by the end of treatment and 14% had cleared up partially, with a global response rate of 100%. The mean number of sessions was 15 (6 to 46 sessions) corresponding to a mean treatment duration of 2 months. The mean cumulative dose was 5 J/cm(2) (1.3 to 16.1 cm(2)). Follow-up was performed in 19 lesions for a median period of 15 months (8 to 26 months). Persistent complete clearance was observed in 13 of 19 (68%) lesions (12 patch-stage and 1 plaque). Continued partial clearance was noted in 3 lesions (1 patch-stage and 2 plaques) (16%). Two lesions (both patch-stage) (11%) showed relapse 7 months after the end of treatment. The sole nodule in the study showed no response to treatment. Histological and immunohistological were consistent with clinical results and showed histological healing where lesions had clinically disappeared, except for one case with persistence of a few mycosis cells in the epidermis despite a clinical appearance of healing. Discussion. This study demonstrates the efficacy of 308 nm excinner laser in stage la of mycosis fungoides. Given its limited availability and high cost, 308 nm excimer laser may be used as second-line therapy after failure of treatment with topical steroids.