Sentinel node identification rate, but not accuracy, is significantly decreased after pre-operative chemotherapy in axillary node-positive breast cancer patients

Background: The aim was to prove the low identification rate of sentinel lymph node biopsy (SNB) and to determine the feasibility of replacing axillary lymph node dissection (AND) in axillary lymph node positive patients after chemotherapy. Methods: From October 2001 to July 2005, 875 consecutive patients with primary operable breast cancer underwent SNB and AND. Among them, 238 received pre-operative chemotherapy. We compared the identification rate, false negative rate (FNR), negative predictive value (NPV), and accuracy of SNB in clinically node-positive patients with or without chemotherapy. Results: The identification rate was significantly lower in patients received chemotherapy (77.6%) than in those not received it (97.0%) (P < 0.001). In those received the therapy, the FNR was 5.6%, the NPV was 86.8%, and the accuracy was 95.9%. In those not received therapy, the FNR was 7.4% and the accuracy was 92.6% (differences not statistically significant). Conclusion: The identification rate in confirmed axillary lymph node-positive patients was significantly lower in patients received pre-operative chemotherapy, but accuracy did not differ significantly between the two groups. Thus, for patients who achieve complete axillary clearance by chemotherapy, SNB could replace AND.