Clinical Outcomes of Hypofractionated Whole Breast Irradiation in Early Stage, Biologically High-Risk Breast Cancer.

PURPOSE: 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. METHODS AND MATERIALS: 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. RESULTS: 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. CONCLUSIONS: Our data support the use of moderate HWBI in patients with early-stage, biologically high-risk breast cancer.

Adjuvant radiotherapy improves overall survival when added to surgery and chemotherapy for uterine carcinosarcoma: a surveillance, epidemiology, and end results analysis.

BACKGROUND: Uterine carcinosarcoma (UCS) confers a high recurrence risk following surgery, and adjuvant chemotherapy (CHT) is typically administered in all stages. The benefit of radiation therapy (RT) in UCS, when added to adjuvant CHT, is unknown. We sought to analyze the Surveillance, Epidemiology, and End Results (SEER) database to ascertain whether RT improves overall survival (OS) when added to surgery and CHT for UCS. METHODS: SEER 18 Custom Data registries (Nov 2018 submission) were queried for uterine (ICD10 C54.1-9, C55.9) carcinosarcoma (ICD-0-3 8980-3). Patients with stage I-III UCS who underwent surgery and CHT ± RT were analyzed with univariate analysis (UVA) and multivariable analysis (MVA) using Kaplan-Meier and Cox proportional hazards regression modeling. Propensity-score matched analysis with inverse probability of treatment weighting (IPTW) was performed to account for indication bias. Furthermore, conditional landmark analysis (minimum three-month follow-up) was performed to minimize immortal time bias. RESULTS: All 1541 patients (1988-2016) underwent surgery and CHT and 54% received RT. On UVA, RT improved median and 5-year OS from 41 to 87 months and 43-55%, respectively (HR 0.65, 95% CI 0.56-0.77) (p < 0.001). After IPTW adjustment, RT improved median and 5-year OS from 46 to 65 months and 46-53%, respectively (HR 0.74, 95% CI 0.63-0.87) (p < 0.001). The benefit of RT remained on unadjusted and adjusted MVA and conditional landmark analysis. CONCLUSION: In stage I-III UCS treated with surgery and CHT, receipt of RT is associated with OS benefit. Further prospective data are needed to investigate the RT's benefit in UCS.