Use of breast-conserving surgery for treatment of stage I and stage II breast cancer.

PURPOSE: To assess the use of breast-conserving surgery in two states reported to differ with respect to surgical treatment of breast cancer. METHODS: A retrospective cohort study based on data collected from medical records and patients was performed among 1,514 patients diagnosed with early-stage breast cancer in Massachusetts and 1,061 patients in Minnesota. Patients were identified at 18 randomly selected hospitals in Massachusetts and at 30 hospitals in Minnesota. The rate of breast-conserving surgery in both states and the correlates of breast-conserving surgery among women eligible for the procedure were determined. RESULTS: The rate of breast-conserving surgery in both states was much higher than previously reported. Among those eligible for the procedure, nearly 75% underwent breast-conserving surgery in Massachusetts and nearly half did so in Minnesota. Significantly (P < .003) more women who underwent mastectomy in Minnesota (27%) than in Massachusetts (15%) reported that their surgeon did not discuss breast-conserving surgery with them. Among women who underwent mastectomy and who reported being informed of both surgical alternatives, more women (P < .001) in Minnesota (74%) than in Massachusetts (62%) said they ultimately chose mastectomy because their surgeon recommended it. In Massachusetts, women treated at teaching hospitals were twice as likely as other women to undergo breast-conserving surgery. In Minnesota, women over age 70 and those who lived in rural areas were less likely than other women to undergo breast-conserving surgery. CONCLUSION: Although the rate of breast-conserving surgery in each state was higher than expected based on earlier reports, the rates differed considerably between states. Additional studies are needed to determine whether variation in practice between geographic areas is due to differences in patients' preferences and values or to surgeons' propensity for one type of surgery based on where they practice.