ESTRO 2025 - Abstract Book

S922

Clinical - Haematology

ESTRO 2025

Response assessment was performed at median 3.1 months (1.1-13.8) from end LDRT, with ORR 42/44 (95.5%). With a median follow up of 69.8 months (9-227) from initial RT, there have been 6 in field recurrences, with a local control rate of 84.5% (35/39). All 6 sites were reirradiated (5 LDRT, 1 20Gy/5#). All remain controlled. 15/36 (41.7%) patients have relapsed/progressed. First relapse was in-field in 4 patients, in and out-of-field in 1, and out-of-field in 10. Out of field relapses included 4 contralateral salivary relapses and 7 at distant sites. 3 patients (8.3%) developed high grade lymphoma. Relapse/progression was less common in stage 1, 3/15 (20%) versus 7/15 (46%) with stage II and 5/6 (83.3%) stage IV. Median PFS was 68 months with 5-year PFS 54.3%. Median OS was 140.8 months and 5-year OS 97.1%.