Ultrahypofractionated Low-Dose Total Skin Electron Beam in Advanced-Stage Mycosis Fungoides and Sézary Syndrome

Purpose The aim of this study was to assess the safety and efficacy of an ultrahypofractionated low-dose total skin electron beam therapy (TSEBT) regimen in patients with advanced mycosis fungoides (MF) or Sézary syndrome (SS). Methods and Materials In this multicenter observational study from 5 German centers, 18 total patients with MF or SS underwent TSEBT with a total dose of 8 Gy in 2 fractions. The primary endpoint was the overall response rate. Results Fifteen of 18 patients with stage IIB-IV MF or SS were heavily pretreated with a median of 4 prior systemic therapies. The overall response rate was 88.9% (95% confidence interval [CI], 65.3-98.6), with 3 complete responses (16.9%; 95% CI, 3.6-41.4). At a median follow-up period of 13 months, the median time to next treatment (TTNT) was 12 months (95% CI, 8.2-15.8), and the median progression-free survival was 8 months (95% CI, 2-14). A significant reduction in the modified severity-weighted assessment tool, total Skindex-29 score (Bonferroni-corrected P < .005), and all subdomains (Bonferroni-corrected P < .05) was observed after TSEBT. Half of the irradiated patients (n = 9) developed grade 2 acute and subacute toxicities. One patient had confirmed grade 3 acute toxicity. Chronic grade 1 toxicity has been observed in 33% of patients. Patients with erythroderma/SS or prior radiation therapy appear at higher risk of skin toxicities. Conclusions TSEBT with 8 Gy in 2 fractions achieves good disease control and symptom palliation with acceptable toxicity, greater convenience, and fewer hospital visits. The aim of this study was to assess the safety and efficacy of an ultrahypofractionated low-dose total skin electron beam therapy (TSEBT) regimen in patients with advanced mycosis fungoides (MF) or Sézary syndrome (SS). In this multicenter observational study from 5 German centers, 18 total patients with MF or SS underwent TSEBT with a total dose of 8 Gy in 2 fractions. The primary endpoint was the overall response rate. Fifteen of 18 patients with stage IIB-IV MF or SS were heavily pretreated with a median of 4 prior systemic therapies. The overall response rate was 88.9% (95% confidence interval [CI], 65.3-98.6), with 3 complete responses (16.9%; 95% CI, 3.6-41.4). At a median follow-up period of 13 months, the median time to next treatment (TTNT) was 12 months (95% CI, 8.2-15.8), and the median progression-free survival was 8 months (95% CI, 2-14). A significant reduction in the modified severity-weighted assessment tool, total Skindex-29 score (Bonferroni-corrected P < .005), and all subdomains (Bonferroni-corrected P < .05) was observed after TSEBT. Half of the irradiated patients (n = 9) developed grade 2 acute and subacute toxicities. One patient had confirmed grade 3 acute toxicity. Chronic grade 1 toxicity has been observed in 33% of patients. Patients with erythroderma/SS or prior radiation therapy appear at higher risk of skin toxicities. TSEBT with 8 Gy in 2 fractions achieves good disease control and symptom palliation with acceptable toxicity, greater convenience, and fewer hospital visits.