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.