1. Clinical Outcomes of Hypofractionated Whole Breast Irradiation in Early Stage, Biologically High-Risk Breast Cancer
- Author
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Benjamin D. Willen, Thomas J. Quinn, Muayad F. Almahariq, Peter Y. Chen, M. Saada Jawad, Gregory S. Gustafson, Eva Leung, Michelle Ka Yan Wu, and Joshua T. Dilworth
- Subjects
Oncology ,Humans ,Female ,Breast Neoplasms ,Radiation Dose Hypofractionation ,Radiology, Nuclear Medicine and imaging ,Middle Aged ,Neoplasm Recurrence, Local ,Disease-Free Survival ,Proportional Hazards Models - Abstract
Adoption of hypofractionated whole breast irradiation (HWBI) for patients with early-stage, biologically high-risk breast cancer remains relatively low. We compared clinical outcomes of conventionally fractionated whole breast irradiation (CWBI) versus moderate HWBI in this patient population.We queried a prospectively maintained database for patients with early-stage (T1-2, N0, M0) breast cancer who received whole breast irradiation with either CWBI or moderate HWBI at a single institution. We included only patients with biologically high-risk tumors (defined as either estrogen receptor/progesterone receptor/human epidermal growth factor receptor 2 negative, human epidermal growth factor receptor 2 amplified, and/or patients with a high-risk multigene assay) who received systemic chemotherapy. Inverse probability of treatment weighting was used to compare treatment cohorts and to estimate 5-year time to event endpoints. Hazard ratios (HR) and 95% confidence interval (CI) were determined based on Cox proportional hazards model.We identified 300 patients, of whom 171 received CWBI and 129 received HWBI. There was a statistically significant difference in median age at diagnosis, 59 years for CWBI versus 63 years for HWBI (P = .004), and in median follow-up time, 97 months for CWBI versus 55 months for HWBI (P.001). After accounting for differences in patient and tumor characteristics with inverse probability of treatment weighting, we found similar 5-year freedom from local recurrence (HR, 0.76; 95% CI, 0.14-4.1), freedom from regional recurrence (HR, 3.395% CI 0.15-69), freedom from distant metastasis (HR 3.9, 95% CI 0.86-17), and disease-free survival (HR 0.84; 95% CI, 0.3-2.4), between those treated with CWBI and those treated with HWBI. Results were similar among each of the 3 high-risk subtypes.Our data support the use of moderate HWBI in patients with early-stage, biologically high-risk breast cancer.
- Published
- 2022
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