Locoregional and distant recurrences after breast conserving therapy in patients with triple-negative breast cancer: a meta-analysis

Background: With higher incidence of recurrence, ongoing dispute exists on whether triple-negative breast cancer (TNBC) is a good candidate for breast conserving therapy (BCT).

Objective: We aimed to appraise the safety of BCT in treating TNBC, in comparison with modified radical mastectomy. The prognostic effect of TN phenotype in conservatively managed patients was also assessed.

Methods: A systematic search for studies regarding recurrences in patients with TNBC or treated by BCT was conducted up to March 2013. Summary relative risks (RRs) for ipsilateral locoregional recurrence (ILRR) and distant metastasis (DM) were calculated in a fixed-effects model.

Results: Twenty-two studies concerning 15,312 breast cancer patients were analyzed. In the cohort of TNBC, the patients receiving BCT were less likely to develop ILRR and DM in comparison with mastectomy (RR 0.75, 95% CI 0.65-0.87; RR 0.68, 95% CI 0.60-0.76). In the cohort of BCT, the TN subtype increased the risks of both ILRR and DM than non-TN subtypes (RR 1.88, 95% CI 1.58-2.22; RR 2.12, 95% CI 1.72-2.62). Further subgroup analyses of BCT cohort revealed that the luminal phenotype had the most favorable prognosis. Notably, TN subtype was less likely to develop ILRR than HER-2 subtype (RR 0.69, 95% CI 0.53-0.91), there was no difference in DM rate between them.

Conclusions: BCT benefits patients with TNBC than mastectomy does. However, TN subtype predicts a poorer prognosis than non-TN subtype, suggesting more aggressive adjuvant therapy for TNBC be established in future trials.