ESTRO 2024 - Abstract Book

S1171

Clinical - Haematology

ESTRO 2024

Purpose/Objective:

Based on current literature, about 50% of patients affected by mycosis fungoides (MF) and Sezary syndrome (SS) relapse after allogeneic transplant (AT). Despite this, spare evidence is available for the management of relapsed disease, above all for the use of radiotherapy (RT).

The aim of this study is to evaluate the role of total skin electron beam radiotherapy (TSEBI) in the post-HT setting.

Material/Methods:

We retrospectively analyzed data from 10 consecutive patients affected by MF or SS, who underwent AT and were treated with TSEBI after relapse. All patients were treated at Italian centers. Given the small number of patients, we only performed an observational analysis on outcomes after TSEBI and its safety.

Results:

Each patient received several therapies before AT, including systemic therapy, phototherapy and RT, both local RT and TSEBI. The AT was performed from 2013 to 2022, with a median time from diagnosis to AT of 40 months (range 10-108). The progression free survival (PFS) after AT was 3.6 months (range 1-6). The median time from AT to TSEBI was 8.7 months (range 4-18). TSEBI was performed with the schedule of 20 Gy in 20 fractions in 40% of cases (all TSEBI schedules used are shown in table 1). The best response after TSEBI was complete response (CR) in 3 patients, very good partial response (VGPR) in 5 patients and partial response (PR) in 2 cases. With a median follow up (FUP) of 28.8 months after TSEBI (range 2-82), we observed 9 relapses, with a median PFS of 14.4 months (range 2-60), but 6 out of 10 patients relapsed within 6 months from the end of TSEBI. Of note, patients that experienced a longer PFS were treated with higher RT doses. The overall survival (OS) of the whole cohort was 79 months (range 35-124); at the end of our FUP 3 patients had died (2 for disease progression and one for another cause).