Outcomes following local therapy for early-stage breast cancer in non-trial populations.

Recent studies suggest trends toward more mastectomies for primary breast cancer treatment. We assessed survival after mastectomy and breast-conserving surgery (BCS) with radiation for early-stage breast cancer among non-selected populations of women and among women similar to those in clinical trials. Using population-based data from Surveillance Epidemiology, and End Results cancer registries linked with Medicare administrative data from 1992 to 2005, we conducted propensity score analysis of survival following primary therapy for early-stage breast cancer, including BCS with radiation, BCS without radiation, mastectomy with radiation, and mastectomy without radiation. Adjusted survival was greatest among women who had BCS with radiation (median survival = 10.98 years). Compared with this group, mortality was higher among women who had mastectomy without radiation (median survival 10.04 years, adjusted hazard ratio (HR) = 1.19, 95% confidence interval (CI) = 1.14-1.23), mastectomy with radiation (median survival 10.02 years, HR = 1.20, 95% CI = 1.14-1.27), and BCS without radiation (median survival 7.63 years, HR = 1.81, 95% CI = 1.70-1.92). Among women representative of those eligible for clinical trials (age ≤70 years, Charlson comorbidity score = 0/1, and stage 1 tumors), there were no differences in survival for women who underwent BCS with radiation or mastectomy. In conclusion, after careful adjustment for differences in patient, physician, and hospital characteristics, we found better survival for BCS with radiation versus mastectomy among older early-stage breast cancer patients, with no difference in survival for BCS with radiation versus mastectomy among women representative of those in clinical trials. These findings are reassuring in light of recent trends towards more aggressive primary breast cancer therapy.