ESTRO 2025 - Abstract Book

S542

Clinical - Breast

ESTRO 2025

Results:

In 2023, six women were treated with hypofractionated radiotherapy. One patient had a luminal A subtype, three had luminal B, and two had HER2-positive expression. Three patients had N3 nodal involvement, two had cT4 stage due to cutaneous involvement, and one had cT2N2 disease. All patients received systemic therapy (four with endocrine therapy and two with chemotherapy and biological treatments). After six months, the five patients treated with curative intent showed a reduction in tumor volume, while the one patient treated with palliative intent experienced nodal progression. After 13 months, one patient maintained local control but showed initial mediastinal progression (maybe due to spontaneous interruption of endocrine therapy). Two patients experienced acute grade 2 skin toxicity (erythema), while no other significant toxicities were reported. Conclusion: Definitive moderate hypofractionated radiotherapy provides good local control with acceptable toxicity. However, longer follow-up and a larger sample size are needed to further assess these results.

Keywords: Exclusive Radiotherapy, Hypofractionation

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Digital Poster Cost-effectiveness analysis of Mepitel film for prevention of acute radiation dermatitis in breast cancer: From a Canadian healthcare perspective Shirley SW Tse 1,2 , Henry CY Wong 3 , Flay Charbonneau 4 , Jeffrey Q Cao 5,6 , Tarek Hijal 7 , Marc Kerba 5 , Mark R. Waddle 8 , Shing Fung Lee 9,10 , Stephen T Sonis 11 , Julie Ryan Wolf 12 , Corina van den Hurk 13 , Kimberly Corbin 8 , Gustavo N Marta 14 , Cindy Wong 15 , Raymond Chan 16 , Patries Herst 17 , Rosemary Hill 18 , Edward Chow 4 , Hayeon Kim 19 1 Department of Clinical Oncology, United Christian Hospital, Hong Kong, Hong Kong. 2 Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong, Hong Kong. 3 Department of Oncology, Princess Margaret Hospital, Hong Kong, Hong Kong. 4 Department of Radiation Oncology, University of Toronto, Toronto, Canada. 5 Department of Oncology, University of Calgary, Calgary, Canada. 6 Department of Oncology, Arthur Child Comprehensive Cancer Centre, Calgary, Canada. 7 Department of Oncology, McGill University, Montreal, Canada. 8 Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA. 9 Department of Radiation Oncology, National University Hospital, Singapore, Singapore. 10 Department of Medicine, Yong Loo Lin School of Medicine, Singapore, Singapore. 11 Divisions of Oral Medicine, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, USA. 12 Department of Dermatology, University of Rochester Medical Center, New York, USA. 13 Comprehensive Cancer Centre South, Eindhoven Cancer Registry, Eindhoven, Netherlands. 14 Department of Radiation Oncology, Hospital