Is Breast Conserving Surgery Oncologically Safe for Patients With Multiple Ipsilateral Breast Cancers? A Systematic Review and Meta-analysis.

BACKGROUND

The incidence of multiple ipsilateral breast cancers (MIBC), which includes multifocal and multicentric tumors, is increasing. Despite breast conserving surgery (BCS) being the mainstay of treatment in early breast cancer, it is considered controversial for MIBC due to oncological safety concerns. The aim was to compare oncological outcomes of BCS compared with mastectomy for patients with MIBC.

METHODS

A systematic literature search of relevant databases for comparative studies was conducted. A meta-analysis using the Mantel-Haenszel method was performed to calculate risk ratios (RR) of local recurrence (LR), locoregional recurrence (LRR), distant recurrence (DR), disease-free survival (DFS) and overall survival (OS) for BCS compared with those who had mastectomy for MIBC.

RESULTS

17 studies involving 29,711 (BCS, n = 9587; mastectomy, n = 20,124) patients were included. There were no significant differences in rates of LR (RR 1.06, 95% CI, 0.74-1.51, P = .76), LRR (RR 1.02, 95% CI, 0.68-1.52, P = .93), DR (RR 0.78, 95% CI, 0.54-1.12, P = .18) or DFS (RR 0.82, 95% CI, 0.60-1.13, P = .23) between both groups. BCS was associated with significantly improved OS compared with mastectomy (RR 0.60, 95% CI, 0.43-0.82, P = .002), however, this was not maintained in a sensitivity analysis restricted to upfront surgery cohorts (RR 0.77, 95% CI, 0.31-1.91, P = .57).

CONCLUSION

BCS appears to achieve comparable oncological outcomes to mastectomy in patients with MIBC, provided that negative margins are obtained and adjuvant radiotherapy is given. However, these findings should be interpreted with caution given study heterogeneity and potential selection bias.