Meta-analysis of sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with initial biopsy-proven node-positive breast cancer

Background: Neoadjuvant chemotherapy for breast cancer has the potential to achieve a pathological complete response in up to 40 per cent of patients, converting disease that was initially node-positive to node-negative. This has raised the question of whether sentinel lymph node biopsy could be an alternative to axillary lymph node dissection in these patients. The aim was to undertake a systematic review and meta-analysis of the accuracy and reliability of sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with initial biopsy-proven node-positive breast cancer. Methods: A literature search was conducted using PubMed, Ovid MEDLINE, Embase and Web of Science databases up to 30 April 2017. Inclusion criteria for studies were pathological confirmation of initial node-positive disease, and sentinel lymph node biopsy performed after neoadjuvant chemotherapy followed by axillary lymph node dissection. Results: A total of 13 studies met the inclusion criteria and were included in the analysis (1921 patients in total). The pooled estimate of identification rate was 90 (95 per cent c.i. 87 to 93) per cent and the false-negative rate was 14 (11 to 17) per cent. In subgroup analysis, the false-negative rate with use of dual mapping was 11 (6 to 15) per cent, compared with 19 (11 to 27) per cent with single mapping. The false-negative rate was 20 (13 to 27) per cent when one node was removed, 12 (5 to 19) per cent with two nodes removed and 4 (0 to 9) per cent with removal of three or more nodes. Conclusion: Sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with biopsy-proven node-positive breast cancer is accurate and reliable, but requires careful patient selection and optimal surgical techniques.