ESTRO 2025 - Abstract Book

S2208

Interdisciplinary – Education in radiation oncology

ESTRO 2025

4484

Digital Poster Reirradiation in clinical practice. A day-to-day challenge for the radiotherapy team.

Mihaela Dumitru 1 , Laura Rebegea 1,2,3 , Rodica Anghel 4 , Mihaela Lungu 5,2 , Claudia Pavel 1 , Mihai Dumitrache 6 1 Radiotherapy, “Sfantul Apostol Andrei” Emergency Clinical Hospital, Galati, Romania. 2 Clinical - Medical, Faculty of Medicine and Pharmacy, “Dunarea de Jos” University, Galati, Romania. 3 Research Center in the Field of Medical and Pharmaceutical Sciences, ReFORM-UDJ, “Dunarea de Jos” University, Galati, Romania. 4 Oncology, ”Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania. 5 Neurology, “Sfantul Apostol Andrei” Emergency Clinical Hospital, Galati, Romania. 6 Radiotherapy, Central Military Emergency University Hospital "Dr. Carol Davila"ostol Andrei” Emergency Clinical Hospital, Bucharest, Romania Purpose/Objective: Reirradiation has become an important therapeutic option in the last years, increasingly performed being considered a valuable salvage option and also with radical intent. The most important issue of this therapy is the severity of the radiation response of the normal organs at risk, which limits the planned and delivered radiation dose. The correlation between mathematical equivalence formulas and clinical effects of radiobiological origin is weak and the lack of knowledge of the α/β ratio of healthy tissues remains an obstacle to the extensive use of these formulas. Assessment of cumulative doses in reirradiation is both challenging and time consuming. Material/Methods: In our Radiotherapy Department (“Sfantul Apostol Andrei” Emergency Clinical Hospital Galati, Romania), between January 2022 – June 2024 we made reirradiation for 95 patients with 104 reradiated sites, with median age 68 years (range 36 – 89), 49 males (51.58 %) and 46 females (48,42%); median follow-up was 15 months (range 3 -30 months). Inclusion criteria were ECOG status 0-2, histological cancer confirmation, minimum 6 months from previous irradiation, without grade 4 toxicities during first irradiation course, highly conformal techniques available, cases approved in multidisciplinary team. Results: Factors and parameters taken into consideration for optimal re-irradiation scenario, used in our clinic for re irradiation planning are: fractionation schemas, dose constraints, radiotherapy technique, biological dose estimation, organs at risk and its cumulative doses. With curative and respective palliative intent we had 11 cases (10.58%) and respective 93 sites (89.42%). The most frequent reirradiated sites, for palliative scope, was bone metastasis in 23 / 93 sites (24.73%), and for curative scope, rectum was most frequent neoplasia, in 6 /11 cases (54.55%). Regarding fractionation schema, TD=30 Gy/10 fractions, for palliative intent, in 34 / 93 palliative cases (36.56%) was used; for curative intent TD=50Gy/ 25 fractions, in 6/11 cases (54.55%) were most frequently used. We did not used hyper-fractionation schemas. The time interval between two radiotherapy courses was over 24 months in 44 cases (42.31%). The most used technique was volumetric arc modulated radiotherapy. None of our re irradiated patients experienced grade 3 or 4 acute and late toxicity, the quality of life has been significantly improved due to the pain, bleeding compressive syndrome’s control and also, overall survival has been increased. Conclusion: Reirradiation remains a challenge for radiotherapy team because literature data are limited regarding cumulative doses at organ at risk, and also, are limited evidences from prospective reirradiation trials.

Keywords: reirradiation, radiobiology, challenge

References: Lee SF, Hoskin PJ. Re-irradiation practice and ESTRO/EORTC consensus recommendations: 2023 ASTRO education panel. Ann Palliat Med. 2024 Jul;13(4):1150-1153. doi: 10.21037/apm-24-4. Epub 2024 May 28. PMID: 38859596. Maciejewski BA, Gabryś D, Napieralska A. Re-irradiation: the “some like it hot – others not” dilemma. NOWOTWORY J Oncol 2024; 74: 123–133.