LAUSR

ABSTRACT OBJECTIVES Historically, the standard of care for total skin electron beam therapy (TSEBT) delivered 30-36 Gray (Gy) over 5-10 weeks. Given the high-risk of relapse, a majority of patients require additional treatments. Therefore, attempts to utilize a shortened course of TSEBT have been investigated. METHODS We conducted a single-institution retrospective review to evaluate disease response, control, and toxicity using a low-dose, hypofractionated course of TSEBT (HTSEBT) in patients with mycosis fungoides. RESULTS 40 patients received 57 courses of HTSEBT. Median dose (Gy)/fractionation was 12 / 3, spanning a median time of 2.4 weeks. Overall response rate of patients assessed (n=54) was 100%. Thirty-one courses (57.4%) resulted in a complete response and 23 courses (42.6%) resulted in a partial response. Cumulative incidence of progressive skin disease at 3 months was 37.2%, at 6 months, 56.9%, and at 1 year, 81.5%. Of the 40 patients treated with a first course of HTSEBT, 31 received subsequent courses of RT. Cumulative incidence of subsequent treatment was 28.0% at 3 months, 46.8% at 6 months, and 70.0% at one year. Patients who underwent repeat courses of HTSEBT continued to have similar treatment responses to repeat courses without increased toxicities. Toxicities from all courses were acceptable with the exception of one patient who experienced grade 4 skin toxicity (moist desquamation requiring hospitalization). CONCLUSIONS Low-dose, HTSEBT provides good palliation in patients with CTCL with a satisfactory response and toxicity profile. HTSEBT allows therapy to be completed in far fewer treatments. Low-dose HTSEBT is an appropriate treatment option for patients unable to come for daily treatment. HTSEBT provides a way to decrease exposure to other patients and staff during public health emergencies such as the COVID-19 pandemic.