Extent of resection in breast conserving surgery after neoadjuvant chemotherapy: a literature review.

Background and Objective: Neoadjuvant chemotherapy (NACT) could cause tumor shrinkage and result in a higher rate of breast conservation. However, the extent of resection in breast conserving surgery (BCS) following NACT remained unclear. We conducted a literature review to determine the extent of resection in BCS after NACT. Methods: A PubMed search was conducted for relevant articles from 1 Key Content and Findings: Six studies (171 patients) and 11 studies (2,276 patients) with original and residual tumor resection respectively were reviewed. The average re-excision rates were 6.3% (range, 0-10.3%) and 9.6% (range, 0-19.2%) respectively. Average local recurrence rates were 10.9% (range, 7.7-14%) and 3.5% (range, 0.65-7.6%) after a follow-up of 44 (range, 36-51.9) and 49.8 (range, 19-86.4) months in patients with original and residual tumor resection respectively. Comparing patients with resection of residual tumor with various groups of patients who had undergone upfront surgery or mastectomy or resection of the original tumor bed, the studies did not demonstrate a statistically significant difference in terms of margin status and oncological outcomes. Conclusions: Limited and heterogenous data exist on the extent of resection in BCS after NACT. No statistically significant difference was demonstrated by the studies in terms of re-excision rates and oncological outcomes between the two groups. These findings require validation in larger well-designed studies.