Associations Between Hospital Volume and Overall Survival After Surgery in Older Patients with Breast Cancer.

BACKGROUND: High-volume hospitals (HVHs) are associated with improved overall survival (OS) following surgery for breast cancer compared with low-volume hospitals (LVHs). We examined this association in patients age ≥ 80 years and described patient and treatment characteristics associated with HVHs. PATIENTS AND METHODS: The National Cancer Database was queried for women age ≥ 80 years who underwent surgery for stage I-III breast cancer between 2005 and 2014. Hospital volume was defined as the average number of cases during the year of the patient's index operation and the year prior. Hospitals were categorized into HVHs and LVHs using penalized cubic spline analysis of OS. A cutoff of ≥ 270 cases/year defined HVHs. RESULTS: Among 59,043 patients, 9110 (15%) were treated at HVHs and 49,933 (85%) at LVHs. HVHs were associated with more non-Hispanic Black and Hispanic patients, earlier stage disease (stage I 54.9% vs. 52.6%, p < 0.001), higher rates of breast-conserving surgery (BCS) (68.3% vs. 61.4%, p < 0.001), and adjuvant radiation (37.5% vs. 36.1%, p = 0.004). Improved OS was associated with surgery at a HVH (HR 0.85, CI 0.81-0.88), along with receipt of adjuvant chemotherapy (HR 0.73, CI 0.69-0.77), endocrine therapy (HR 0.70, CI 0.68-0.72), and radiation (HR 0.66, CI 0.64-0.68). CONCLUSIONS: Among patients with breast cancer age ≥ 80 years, undergoing surgery at a HVH was associated with improved OS. Patients who completed surgery at HVHs had earlier stage disease and more commonly received adjuvant radiation when appropriate. Processes of care at HVHs should be identified to improve outcomes in all settings.