Resumen de Relationship Between Number of Breast Cancer Operations Performed and 5-Year Survival After Treatment for Early-Stage Breast Cancer
Mary Ann Gilligan, Joan Neuner, Hui Zhang, Rodney Sparapani, Purushottam W. Laud, Ann B. Nattinger
Objectives. We examined the association between number of breast cancer operations performed in a hospital (hospital volume) and all-cause and breast cancer?specific mortality using a national database and statistical methods appropriate for clustering and reducing confounding.Methods. In a retrospective cohort study, we linked Surveillance, Epidemiology, and End Results tumor registry data with Medicare claims data. The cohort included 11225 Medicare patients who had undergone surgery for early-stage breast cancer from 1994 to 1996 in 457 different hospitals. Primary outcomes were all-cause and breast cancer?specific survival rates at a mean follow-up time of 62.5 months.Results. In comparison with treatment in a low-volume hospital, treatment in a high-volume hospital was associated with hazard ratios of 0.83 (95% confidence interval [CI]=0.75, 0.92) for all-cause mortality and 0.80 (CI=0.66, 0.97) for breast cancer?specific mortality.Conclusions. An association between the volume of breast cancer operations performed in a hospital and 5-year survival rates was observed for both all-cause and breast cancer?specific mortality. Further work investigating the aspects of hospital volume that contribute to increased survival is warranted.
