Re-examining the significance of surgical volume to breast cancer survival and recurrence versus process quality of care in Taiwan.

OBJECTIVE: This study explored the association of surgical volume versus process quality with breast cancer survival and recurrence. DATA SOURCES/STUDY
SETTING: Population-based cancer registration data and National Health Insurance claim data. STUDY
DESIGN: This population-based study linked Taiwan's Cancer Database with Taiwan's National Health Insurance Database to collect data on all patients diagnosed with breast cancer in 2003-2004 who received surgical treatment. PRINCIPAL
FINDINGS: This study included 6,396 female breast cancer patients, reported by 26 hospitals. After controlling for patient and provider characteristics, Cox's regression models did not reveal any association between a physician's surgical volume and breast cancer recurrence or survival, although hospital volume was marginally associated with positive 5-year recurrence (HR: 1.001, 95%CI: 1.000, 1.001). After controlling for hospital or physician volume of surgery, we found a significant association between quality of care and both 5-year survival and recurrence. Random effects were also identified between patients and providers based on 5-year survival and 5-year recurrence.
CONCLUSIONS: Process quality of care was significantly more related to survival or recurrence than to surgical volume. The random effects found within hospital-patient clustered data indicated that the effect of the clustered feature of this data should be considered when performing volume-outcome related studies. © Health Research and Educational Trust.