Relationship between number of breast cancer operations performed and 5-year survival after treatment for early-stage breast cancer.
OBJECTIVE
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.
Gilligan
Mary Ann
MA
Department of Medicine and Health Policy Institute, Medical College of Wisconsin, Milwaukee 53226, USA. gilligan@mcw.edu
Neuner
Joan
J
Zhang
Xu
X
Sparapani
Rodney
R
Laud
Purushottam W
PW
Nattinger
Ann B
AB
D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis / Q000401:mortality* / Q000601:surgery*; D002423:Cause of Death; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008408:Mastectomy / Q000706:statistics & numerical data; D015412:Mastectomy, Segmental / Q000706:statistics & numerical data; D006278:Medicare / Q000706:statistics & numerical data; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D018570:Risk Assessment; D018426:SEER Program; D013503:Surgery Department, Hospital / Q000592:standards* / Q000706:statistics & numerical data*; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology