ESTRO 2025 - Abstract Book

S466

Clinical - Breast

ESTRO 2025

the no-NST group (2.9% vs. 9.4%, p=0.023), but after 3 months onwards, no significant differences in treatment related toxicity were observed. The median time between diagnosis and questionnaires completion was 3.1 years (IQR 1.6-5.2). Median total scores for the EORTC-QLQ-C30 (83.5 vs. 84.1, p=0.437) and -BR23 (76.7 vs. 76.5, p=1.000) were similar between groups. Breast satisfaction scores were 76.5 in the NST group and 69.0 in the no-NST group (p=0.198). Subgroup analysis showed smaller TRVs for cT2 patients after NST (281.7 vs. 423.9 cm 3 , p=0.005).

Conclusion: NST reduced TRVs only in cT2 tumors, and increased boost frequency with lower boost volumes in all breast cancer patients. However, increased volumes of healthy breast tissue were removed in the NST-group compared to no NST. Quality of life and cosmetic outcomes was similar in both groups.

Keywords: Cosmetic result, neoadjuvant therapy, boost volume

References:

1. Common Terminology Criteria for Adverse Events (CTCAE) Version 5. National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services.