Ductal carcinoma in situ with microinvasion (
DCIS-MI) is a subtype of
breast cancer with a good prognosis, for which both
breast conserving surgery plus
radiotherapy (BCS + RT) and
mastectomy are feasible surgical methods, but no clear conclusion has been made on the choice of these treatments. We used the Surveillance, Epidemiology and End Results database to extract 5432
DCIS-MI patients. Participants were divided into the BCS + RT group and the
mastectomy group. We compared the overall survival (OS) and
breast cancer-specific survival (BCSS) of the two groups using the Kaplan-Meier method and Cox regressions before and after propensity score matching (PSM). Before PSM, both univariate and multivariate analyses showed that BCS + RT group had significantly higher OS and BCSS compared with patients in the
mastectomy group (P < 0.001). After PSM, the multivariate analysis showed that compared with
mastectomy, the BCS + RT showed significantly higher OS and BCSS (HR = 0.676, 95% CI = 0.540-0.847, P < 0.001; HR = 0.565,95% CI = 0.354-0.903, P = 0.017). In addition, the subgroup analysis showed that BCS + RT is at least equivalent to
mastectomy with respect to OS and BCSS in any subgroup. For patients with
DCIS-MI, the prognosis of BCS + RT was superior to
mastectomy.