Effect of re-excision on local recurrence in patients with involved or close margins after upfront breast-conserving surgery: a systematic review and meta-analysis

Background: Involved margins after breast-conserving surgery are associated with increased risk of local recurrence. A systematic search and meta-analysis was conducted to investigate the still-unclear role of re-excision in reducing this risk. Methods: A systematic search of the English-language literature up to May 31, 2024, was performed using PubMed and Embase databases. Studies that met the following criteria were included in the meta-analysis: available full data, patients with breast cancer, involved or close margins after breast-conserving surgery, and comparison of local recurrence rates between patients who underwent re-excision and those who did not. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated using the random effects model. Bias risk was assessed with Begg-Mazumdar and Egger tests. Results: Eight papers and 13 datasets were included in the analysis. Studies differed by sample selection: inclusion of patients with close margins and of both patients with invasive cancer and carcinoma in situ. Of the total 3728 patients, 1897 underwent re-excision and 1831 did not. The mean OR of local recurrence after re-excision was 1.034 (95% CI 0.656—1.629), with a p-value of 0.885. The mean OR of local recurrence after re-excision in patients with DCIS was 2.065 (95% CI 0.96 – 4.442), with a p-value of 0.063, and in patients with 10-years follow-up the mean OR was 1.47 (95% CI 0.75 – 2.86) with a p-value of 0.26. Conclusion: The local recurrence rate in this study did not differ between patients with involved or close margins after breast-conserving surgery who had or did not have additional surgery. The absence of local control effect remained in those with longer follow-up. A trend toward an increased risk of local recurrence was observed in patients with carcinoma in situ who underwent re-excision; however, this finding did not reach statistical significance. Thus, we recommend against routine re-excision and suggest it should be carried out only in selected cases, after thorough discussion of a multidisciplinary team.