Local Recurrence and Survival Outcomes of Multifocal/Multicentric Breast Cancer After Breast Conserving Therapy: A systematic Review and Meta-Analysis.

Background: The appropriateness of BCT for MF/MCBC is debated, with concerns about higher recurrence rates. This study aims to provide an updated systematic review and meta-analysis of LR and survival outcomes for MF/MCBC patients undergoing BCT.

Methods: PubMed, Web of Science, Embase, and the Cochrane Library were searched up to May 2024. Eligible studies included original research articles comparing LR, DFS, or OS in patients with MF/MC or UF breast cancer undergoing BCT or mastectomy. Meta-analyses for LR were conducted using the Mantel-Haenszel method. Published Kaplan-Meier curves for DFS and OS were digitized and aggregated to estimate summary survival curves.

Results: 21 studies were included in the meta-analysis for LR, comprising 28,589 participants, and 7 studies for survival analysis. The meta-analysis revealed that MF/MC breast cancer patients undergoing BCT had a significantly higher LR rate compared to UF patients (OR = 1.76, 95% CI: 1.24-2.49, P = .002), though recent studies indicated comparable LR rates. No significant difference in LR was found between MF/MC patients treated with BCT versus mastectomy (OR = 1.72, 95% CI: 0.96-3.10, P = .07). The estimated 3-, 5-, and 8-year DFS rates were 92.4%, 88.3%, and 84.5%, respectively, while the OS rates were 98.0%, 95.8%, and 91.8%.

Conclusion: BCT for MF/MC breast cancer was associated with higher LR rates compared to UF breast cancer, but the disparity was reducing in recent years. BCT offers comparable LR outcomes to mastectomy in MF/MC patients. Survival outcomes for MF/MC patients treated with BCT were favorable, affirming its oncological safety.