Low-dose total skin electron beam therapy as an effective modality to reduce disease burden in patients with mycosis fungoides: Results of a pooled analysis from 3 phase-II clinical trials

Background: Standard-dose (36-Gy) total skin electron beam therapy (TSEBT) is a highly effective treatment in mycosis fungoides. However, the regimen is time-intensive and may be associated with significant toxicity. Objective: We sought to evaluate the efficacy and tolerability associated with low-dose (12-Gy) TSEBT. Methods: Data from 3 clinical trials using low-dose (12-Gy) TSEBT were pooled. In all trials, TSEBT-naïve patients with stage IB to IIIA mycosis fungoides were treated with TSEBT (12 Gy, 1 Gy per fraction over 3 weeks). The primary end point was clinical response rate. Secondary end points included time to response and duration of clinical benefit. Results: In all, 33 patients enrolled. Eighteen were male; stages were 22 IB, 2 IIA, 7 IIB, and 2 IIIA. Overall response rate was 88% (29/33), including 9 patients with complete response. Median time to response was 7.6 weeks (3-12.4 weeks). Median duration of clinical benefit was 70.7 weeks (95% confidence interval 41.8-133.8 weeks). Toxicities from TSEBT were mild and reversible. Limitations: Conclusions are limited because of the small number of patients. Conclusions: Low-dose TSEBT provides reliable and rapid reduction of disease burden in patients with mycosis fungoides, which could be administered safely multiple times during the course of a patient's disease with acceptable toxicity profile.