Ultimate results of radiation therapy for T1-T2 mycosis fungoides (including reirradiation)

Abstract

Purpose We report on our experience in the treatment of T1 and T2 mycosis fungoides (MF) with total skin electron beam therapy (TSEBT), with respect to relapse-free rate, overall survival rate, and management of recurrence. Methods and materials Between 1975 and 2001, 141 patients with MF were referred to the radiotherapy department for treatment by TSEBT. A total of 57 patients were staged as having T1 or T2 disease (24 T1 and 33 T2 patients). A total of 25 received topical therapy before irradiation. Treatment was delivered through a 6-MeV linear accelerator to a mean total dose of 30 Gy, 2 Gy/day, 4 days/week, for 4 weeks. Close follow-up was initiated without adjuvant therapy. Median age was 61 years (range, 19–84), and median follow-up was 114 months (range, 14–300). Results Three months after completion of TSEBT, the overall response rate was 94.7%. A complete response was achieved in 87.5% of T1 and 84.8% of T2 patients. Thirty-one patients (54.4%) experienced a skin failure (8 with T1 and 23 with T2 disease) within 1 year. Eighteen patients of 31 received a reirradiation as salvage therapy (6 localized treatment with segmental fields of electron beam irradiation and 12-second TSEB delivering 24 Gy in 12 fractions). Two were treated by topical steroids, and 11 received combination therapy with PUVA (2/10), topical (10/10) or systemic (4/10) chemotherapy, or interferon (7/10). After a second course of TSEBT (4 T1 and 10 T2 patients), the 5-year freedom from relapse rate was 70% vs. 39% in patients having received other modalities. For the whole group, 5-year DFS was 50%. The 5/10/15-year OS were 90%/65%/42%, respectively. In univariate analysis, T1 ( p = 0.03), CR after first TSEBT ( p = 0.04), and age younger than 60 ( p < 0.001) were significant prognostic factor for OS. In multivariate analysis, age younger than 60 years was statistically associated with improved OS ( p = 0.001); T stage and completion of CR remained under threshold of significance ( p = 0.059 and p = 0.063, respectively). During the mean 86-month period of follow-up from relapse, a second recurrence was observed in 29% of patients. Conclusions TSEBT is highly effective in early-stage MF without adjuvant therapy. Management of relapses with local radiotherapy or second TSEBT is feasible, time-saving, and cost-effective.