High-dose-rate brachytherapy as monotherapy versus as boost in unfavorable intermediate-risk localized prostate cancer: A matched-pair analysis.

PURPOSE: High-dose-rate brachytherapy as monotherapy (HDR-M), or as a boost combined with external beam radiotherapy (HDR-B), are both suitable treatments for intermediate-risk prostate cancer. However, data directly comparing these two approaches for men with unfavorable intermediate-risk (UIR) patients are lacking. METHODS AND MATERIALS: Patients with NCCN-defined UIR prostate cancer treated from 1997 to 2020 were identified in a prospectively maintained, single institution database. HDR-M and HDR-B patients were matched using three factors: age ±3 years; Gleason score (major and minor); and clinical T stage. Biochemical failure was defined as PSA nadir (nPSA) + 2. Available acute and chronic toxicities are additionally reported. RESULTS: A total of 247 patients were identified (170 receiving HDR-B, 77 receiving HDR-M), ultimately yielding 70 matched pairs (140 patients) for inclusion. The median followup time was 5.2 years for HDR-M compared with 9.3 years for HDR-B (p < 0.001). The two cohorts had similar calculated prostate EQD2 (HDR-B 118 Gy vs. HDR-M 115 Gy, p = 0.977). No significant differences in OS, CSS, DM, LRR, or FFBF were identified. HDR-B had an increased rate of any acute grade 2+ gastrointestinal toxicity and worse acute dysuria and diarrhea. Chronic gastrointestinal and genitourinary toxicity was similar. CONCLUSIONS: These data suggest that HDR brachytherapy as monotherapy is an effective treatment option for selected patients with unfavorable intermediate-risk prostate cancer and provides a more favorable gastrointestinal toxicity profile than HDR-B. Prospective trials should be conducted to refine the selection process for this heterogeneous cohort of patients.

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.