Effect of hospital volume on processes of care and 5-year survival after breast cancer: A population-based study on 25 000 women

PurposeTo compare processes of care and survival for breast cancer by hospital volume in Belgium, based on 11 validated process quality indicators.MethodsThree databases were linked at the patient level: the Cancer Registry, the population and the claims databases. All women with a diagnosis of invasive breast cancer between 2004 and 2006 were selected. Hospitals were classified according to their annual volume of treated patients: <50 (very low), 50–99 (low), 100–149 (medium) and ≥150 patients (high). Cox and logistic regression models were used to test differences in 5-year survival and in achievement of process indicators across volume categories, adjusting for age, tumor grade and stage.ResultsA total of 25 178 women with invasive breast cancer were treated in 111 hospitals. Half of the hospitals (N = 57) treated <50 patients per year. Six of eleven process indicators showed higher rates in high-volume hospitals: multidisciplinary team meeting, cytological and/or histological assessment before surgery, use of neoadjuvant chemotherapy, breast-conserving surgery rate, adjuvant radiotherapy after breast-conserving surgery, and follow-up mammography. Higher volume was also associated with improved survival. The 5-year observed survival rates were 74.9%, 78.8%, 79.8% and 83.9% for patients treated in very-low-, low-, medium- and high-volume hospitals respectively. After case-mix adjustment, patients treated in very-low- or low-volume hospitals had a hazard ratio for death of 1.26 (95% CI 1.12, 1.42) and 1.15 (95% CI 1.01, 1.30) respectively compared with high-volume hospitals.ConclusionSurvival benefits reported in high-volume hospitals suggest a better application of recommended processes of care, justifying the centralization of breast cancer care in such hospitals.