Comparison of Disease-Free Survival of Breast-Conserving Surgery and Mastectomy Using Propensity Score as Inverse Probability Treatment Weighting.

Background: Survival after breast conserving surgery (BCS) vs. modified radical mastectomy (MRM) is a controversial issue. In this study, we want to compare the disease-free survival (DFS) of women who underwent BCS with those treated by MRM. Method: In this historical cohort study, a total of 1097 women who were diagnosed with breast cancer between 2001 and 2007 and received modified MRM or BCS were entered into the study and followed up to March 2017. Kaplan-Meier estimator and extended cox model, and Cox proportional hazards model with propensity score weighting were implemented to compare overall survival between two groups. Results: A total of 283 women with a maximum follow-up of 11.1 years and age 47.17 ± 11.278 were met the inclusion criteria. The results of the extended cox model did not show any difference between the survival of two groups (P = 0.35). After implementing the Cox model with propensity score weighting, the inferences remained unchanged (P = 0.67). Conclusion: The patients treated with BCS tend to have the same DFS rate as those who underwent a mastectomy in a randomized controlled trial-like setting using propensity score weighting. [ABSTRACT FROM AUTHOR]