Sentinel lymph node surgery after neoadjuvant chemotherapy is accurate and reduces the need for axillary dissection in breast cancer patients

OBJECTIVE: Sentinel lymph node (SLN) surgery is widely used for nodal staging in early-stage breast cancer. This study was performed to evaluate the accuracy of SLN surgery for patients undergoing neoadjuvant chemotherapy versus patients undergoing surgery first. SUMMARY BACKGROUND DATA: Controversy exists regarding the timing of SLN surgery in patients planned for neoadjuvant chemotherapy. Proponents of SLN surgery after chemotherapy prefer a single surgical procedure with potential for fewer axillary dissections. Opponents cite early studies with low identification rates and high false-negative rates after chemotherapy. METHODS: A total of 3746 patients with clinically node negative T1-T3 breast cancer underwent SLN surgery from 1994 to 2007. Clinicopathologic data were reviewed and comparisons made between patients receiving neoadjuvant chemotherapy and those undergoing surgery first. RESULTS: Of the patients, 575 (15.3%) underwent SLN surgery after chemotherapy and 3171 (84.7%) underwent surgery first. Neoadjuvant patients were younger (51 vs. 57 years, P < 0.0001) and had more clinical T2-T3 tumors (87.3% vs. 18.8%, P < 0.0001) at diagnosis. SLN identification rates were 97.4% in the neoadjuvant group and 98.7% in the surgery first group (P = 0.017). False-negative rates were similar between groups (5/84 [5.9%] in neoadjuvant vs. 22/542 [4.1%] in the surgery first group, P = 0.39). Analyzed by presenting T stage, there were fewer positive SLNs in the neoadjuvant group (T1: 12.7% vs. 19.0%, P = 0.2; T2: 20.5% vs. 36.5%, P < 0.0001; T3: 30.4% vs. 51.4%, P = 0.04). Adjusting for clinical stage revealed no differences in local-regional recurrences, disease-free or overall survival between groups. CONCLUSIONS: SLN surgery after chemotherapy is as accurate for axillary staging as SLN surgery prior to chemotherapy. SLN surgery after chemotherapy results in fewer positive SLNs and decreases unnecessary axillary dissections.