Comparison of local recurrence after mastectomy for pure ductal carcinoma in situ with close or positive margins: A meta-analysis

Background: There is controversy regarding the relationship between margin status and risk of local recurrence (LR) in patients with Ductal carcinoma in situ(DCIS) treated by mastectomy. Purpose: We sought to assess the LR rates for patients with DCIS breast cancer treated by mastectomy with respect to the resection margin (RM) status. Materials and Methods: Systematic search of MEDLINE, EMBASE, and Cochrane library published was performed. Studies of pure DCIS breast cancer with treatment of mastectomy and studies that reported surgical RM and LR were included. Results:A total of 12 retrospective studies were included, encompassing 2902 patients with a mean follow-up of 86.4 months. Overall LR rates were 5.3% (27/508) for positive or close margins and 1.6% (37/2367) for negative margin, and most of the recurrences (93.7%) are invasive cancers. Patients with positive or close margins showed a 3.72-fold (95% confidence interval [CI] = 2.30-6.01,P < 0.01, I[2] = 11%) higher risk of LR than patients with negative margin. Patients with positive margin showed a 2.91-fold (95% CI = 1.14-7.41,P = 0.03, I[2] = 0%) higher risk of LR than patients with close margin. Postmastectomy radiation therapy (RT) was not associated with a decreased risk of LR (Risk ratio 0.50; 95% CI = 0.06-4.08,P= 0.52, I[2] = 0%) in patients with positive or close margins. Conclusions: The RM status after mastectomy has a great impact on LR. However, the recurrence rate was insufficient to warrant a recommendation for postmastectomy RT in patients with close or positive margins.