Outcomes of Immediate Breast Reconstruction in Triple Negative Breast Cancer

PURPOSE: IBR is an increasingly more popular surgery following mastectomy for breast cancer. Triple negative breast cancer (TNBC) accounts for around 15% of all breast cancer cases.1 Patients with TNBC are known to have a higher association with disease recurrence and mortality compared with non-TNBC patients. A recent systematic review summarizing available therapies for TNBC patients reported cytotoxic chemotherapy as the mainstay of treatment.2 MIBR poses a higher risk of postoperative complications, which in TNBC patients may pose a serious risk to oncological outcomes. The main objective of the present study was to evaluate the oncological safety of immediate breast reconstruction in a population of patients with breast cancer comparing TNBC and non-TNBC patients. METHODS: A 6-year prospectively maintained database at The Ottawa Hospital between January 1, 2013 and May 31, 2019 was reviewed. Patients with distant metastasis, locoregional recurrence, and neoadjuvant therapy history were excluded. Propensity-score matching with logistic regression methods was performed to compare oncological outcomes in TNBC and non-TNBC patients. Propensity-score matching was performed using the nearest-neighbour method and a matching ratio of 2:1. Kaplan-Meier and log rank tests were performed to performed to provide statistical comparison of disease-free interval (DFI). Outcomes of interest included delays to adjuvant therapy, postoperative complications, and DFI. DFI was defined as time from MIBR to locoregional recurrence or disease-specific mortality. Cox regression survival was used to estimate the risk of locoregional recurrence. P values of <0.05 and 95% confidence interval excluded 1.0 were considered statistically significant. RESULTS: Of the 277 eligible patients, 153 patients were matched. The cohort consisted of 51 (33%) TNBC and 102 (67%) non-TNBC patients after propensity-score matching according to age, tumor stage, and disease grade. The mean follow-up was 3.3-years (±1.6) in TNBC and 3.0-years (±1.8) in non-TNBC patients (P = 0.4). The rates of delays to first radiochemotherapy [17 (33%) versus 14 (14%), P = 0.1], postoperative complications [13(26%) versus 34(33%), P = 0.5], or locoregional recurrence [2 (1.96%) versus 1 (1.96%), P = 1] were statistically similar in TNBC and non-TNBC. Overall survival was not significantly different comparing TNBC and non-TNBC patients (P > 0.05). DFI was not significantly different comparing TNBC and non-TNBC patients (log-rank P = 1.0). Cox regression demonstrated a 12% higher risk of locoregional recurrence in the TNBC compared with the non-TNBC patients, which was not statistically significant [aHR: 1.12, 95% CI: 0.102, 12.42, P = 0.924]. CONCLUSIONS: Our 6-year retrospective cohort study used propensity-score matching to compare oncological outcomes among TNBC patients compared with matched non-TNBC patients. Our findings demonstrated that TNBC was not associated with worse oncological outcomes, including DFI. We excluded women with worse prognosis, which warrants caution when interpreting our findings. Overall, IBR is safe to offer certain TNBC patients from an oncological perspective. REFERENCES: 1. Dent R, Trudeau M, Pritchard K, et al. Triple-negative breast cancer: clinical features and patterns of recurrence. Clin Caner Res. 2007;13(15): 4429–4434. https://doi.org/10.1158/1078-0432.ccr-06-3045 2. Diana A, Franzese E, Centonze S, et al. Triple-negative breast cancers: systematic review of the literature on molecular and clinical features with a focus on treatment with innovative drugs. Curr Oncol Rep. 2018;20(10):1–11. https://doi.org/10.1007/s11912-018-0726-6