Sentinel Lymph Node Surgery After Neoadjuvant Chemotherapy is Accurate and Reduces the Need for Axillary Dissection in Breast Cancer Patients

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.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.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.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.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.