Breast cancer recurrence after immediate and delayed postmastectomy breast reconstruction—A systematic review and meta-analysis

Background: Oncological safety of different types and timings of PMBR after breast cancer remains controversial. Lack of stratified risk assessment in literature makes current clinical and shared decision-making complex. This is the first systematic review and meta-analysis to evaluate differences in oncological outcomes after immediate versus delayed postmastectomy breast reconstruction (PMBR) for autologous and implant-based PMBR separately. Methods: A systematic literature search was performed in MEDLINE, Cochrane Library, and Embase. The Cochrane Collaboration Handbook and Meta-analysis Of Observational Studies in Epidemiology checklist were followed for data abstraction. Variability in point estimates attributable to heterogeneity was assessed using I2-statistic. (Loco)regional breast cancer recurrence rates, distant metastasis rates, and overall breast cancer recurrence rates were pooled in generalized linear mixed models using random effects. Results: Fifty-five studies, evaluating 14,217 patients, were included. When comparing immediate versus delayed autologous PMBR, weighted average proportions were: 0.03 (95% confidence interval [CI], 0.02–0.03) versus 0.02 (95% CI, 0.01–0.04), respectively, for local recurrences, 0.02 (95% CI, 0.01–0.03) versus 0.02 (95% CI, 0.01–0.03) for regional recurrences, and 0.04 (95% CI, 0.03–0.06) versus 0.01 (95% CI, 0.00–0.03) for locoregional recurrences. No statistically significant differences in weighted average proportions for local, regional and locoregional recurrence rates were observed between immediate and delayed autologous PMBR. Data did not allow comparing weighted average proportions of distant metastases and total breast cancer recurrences after autologous PMBR, and of all outcome measures after implant-based PMBR. Conclusions: Delayed autologous PMBR leads to similar (loco)regional breast cancer recurrence rates compared to immediate autologous PMBR. This study highlights the paucity of strong evidence on breast cancer recurrence after specific types and timings of PMBR. Lay summery: Oncologic safety of different types and timings of postmastectomy breast reconstruction (PMBR) remains controversial. Lack of stratified risk assessment in literature makes clinical and shared decision-making complex. This meta-analysis showed that delayed autologous PMBR leads to similar (loco)regional recurrence rates as immediate autologous PMBR. Data did not allow comparing weighted average proportions of distant metastases and total breast cancer recurrence after autologous PMBR, and of all outcome measures after implant-based PMBR. Based on current evidence, oncological concerns do not seem a valid reason to withhold patients from certain reconstructive timings or techniques, and patients should equally be offered all reconstructive options they technically qualify for.