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Does Breast Reconstruction after Mastectomy for Breast Cancer Affect Overall Survival? Long-Term Follow-Up of a Retrospective Population-Based Cohort

Background: This study compared overall and breast cancer–specific survival using long-term follow-up data among women diagnosed with invasive breast cancer undergoing mastectomy or breast reconstruction. Methods: Retrospective study using population-based data from Ontario Cancer Registry (1980 to 1990) including women receiving breast reconstruction within 5 years after mastectomy and controls of age- and cancer histology–matched women with mastectomy alone. We compared overall and breast cancer–specific survival using an extended Cox hazards model. Secondary analysis examined conditional survival across early, intermediate, and late follow-up. Results: Seven hundred fifty-eight matched pairs formed the cohort, with a median follow-up of 23.4 years (interquartile range, 1.1 to 33.0 years). Fewer breast reconstruction patients died overall or from breast cancer compared with controls (overall survival, 44.5 percent versus 56.7 percent, p < 0.0001; breast cancer–specific survival, 31.8 percent versus 42.6 percent, p = 0.0002, respectively). Breast reconstruction was associated with a 17 percent reduced risk of death and a 19 percent reduced risk of breast cancer death, after adjustment (overall survival hazard ratio, 0.83; 95 percent CI, 0.72 to 0.96; breast cancer–specific survival hazard ratio, 0.81; 95 percent CI, 0.68 to 0.99). Among 885 women (58 percent) surviving 20 or more years, there was no difference in risk of death from breast cancer (hazard ratio, 0.59; 95 percent CI, 0.31 to 1.10). Conclusion: In a large cohort with invasive breast cancer followed over 20 years, there is no evidence that breast reconstruction is associated with worse survival outcomes compared with mastectomy alone. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.