Abstract 4695: Post-pandemic evaluation of hypofractionated radiotherapy in preventing acute skin toxicity in multiracial/ethnic breast cancer populations

Abstract Background: Acute skin toxicity is a prevalent and debilitating side effect of radiotherapy (RT) for breast cancer, disproportionately impacting minority populations. Hypofractionated radiotherapy (HF-RT), which involves delivering higher doses of radiation over fewer treatment sessions, has emerged as a preferred approach during the COVID-19 pandemic due to its efficiency and convenience. This study evaluates the effectiveness of HF-RT compared to conventional fractionated RT (CF-RT) in preventing grade 2+ RT-induced skin toxicity among diverse racial and ethnic groups post-pandemic. Objective: To investigate the severity and frequency of RT-induced skin toxicity among breast cancer patients treated with HF-RT and CF-RT, as well as the associations between toxicity and patient demographics or clinical characteristics. Methods: A retrospective analysis was conducted using data from 105 breast cancer patients treated at the Sylvester Comprehensive Cancer Center. Patients were grouped based on RT type: HF-RT (42.5-50 Gy over 3-5 weeks) or CF-RT (50+ Gy over 5-7 weeks). Skin toxicity was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE v5.0). Patients were categorized into HF-RT (n=84), CF-RT (n=15), and partial RT (n=6) groups. Patient demographics, including age, BMI, race/ethnicity, and tumor characteristics, were analyzed for their association with toxicity grades. Statistical analyses were conducted using chi-square tests and multivariate logistic regression. Results: 12.4% of patients experienced grade 2+ skin toxicity at follow-up, with no grade 3 or higher observed. HF-RT patients showed lower grade 2+ toxicity rates (10.7%) compared to CF-RT (26.7%), although the difference was not statistically significant (p=0.143). Age was significantly associated with skin toxicity, with patients aged ≥50 years exhibiting higher rates of grade 2+ toxicity (17.4%) compared to those <50 years (2.8%, p=0.031). Other variables, including BMI, race/ethnicity, tumor stage, and treatment location, were not significantly associated with skin toxicity. HF-RT outcomes were consistent with prior studies, demonstrating safety and feasibility across all racial/ethnic groups, including 55% Hispanic and 11% Black patients. Conclusion: Our findings suggest that HF-RT is feasible and safe for reducing acute skin toxicity in early-stage breast cancer patients across multi-racial/ethnic populations, with outcomes comparable to those reported in prior research conducted predominantly in Caucasian populations. These findings emphasize the importance of tailoring RT regimens to improve survivorship outcomes and address disparities in cancer care. Citation Format: Veronica Zhang Paley, Cristiane Takita, Isildinha M. Reis, Jean L. Wright, Jennifer J. Hu. Post-pandemic evaluation of hypofractionated radiotherapy in preventing acute skin toxicity in multiracial/ethnic breast cancer populations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4695.