Outcomes of Immediate Breast Reconstruction in Triple Negative Breast Cancer: A Propensity Score-Matched Analysis.

Purpose: Triple negative breast cancer (TNBC) patients have a significantly worse prognosis and survival compared to non-TNBC patients. Mastectomy and immediate breast reconstruction (MIBR) is associated with higher rates of complications overall, but whether MIBR significantly increases oncological risk in TNBC patients has not been fully elucidated. Our study aimed to evaluate the oncological safety of MIBR in patients with TNBC compared to non-TNBC.

Methods: A 6-year prospectively maintained retrospective database at The Ottawa Hospital was reviewed from January 1, 2013 to May 31, 2019. Propensity score-matching was performed using the nearest-neighbour method with a matching ratio of 2:1. Kaplan-Meier and log rank tests were performed to provide statistical comparison of disease-free interval (DFI). DFI was defined as time from MIBR to locoregional recurrence or disease-specific mortality. P-value < 0.05 indicated statistical significance.

Results: Of 277 eligible patients, 153 patients were matched. The cohort consisted of 51(33%) TNBC patients and 102 (67%) non-TNBC patients after 2:1 propensity score-matching. The rates of delays to first radiochemotherapy [17 (33%) vs.14 (14%), p = 0.10], postoperative complications [13 (26%) vs. 34 (33%), p = 0.50], and locoregional recurrence [2 (1.96%) vs. 1 (1.96%), p = 1.0] were statistically similar in TNBC and non-TNBC, respectively. DFI was not significantly different in TNBC compared to non-TNBC patients (log-rank p = 1.0). There was no mortality in this cohort.

Conclusions: This 6-year retrospective 2:1 propensity score-matched cohort study demonstrated similar oncological safety for MIBR in patients with TNBC and non-TNBC. Overall, these findings provide additional support for the oncological safety of MIBR in TNBC. Therefore, MIBR remains a therapeutic option for patients with TNBC.