Sentinel node biopsy performed prior to preoperative chemotherapy for axillary lymph node staging in breast cancer

Abstract

Sentinel node (SN) biopsy following preoperative chemotherapy (pCT) in breast cancer patients is associated with a lower identification rate (IR) and an increased false negative rate (FNR) compared to SN biopsy in patients with primary breast cancer. SN biospy was performed in 45 breast cancer patients with a clinical negative axilla prior to pCT. Following chemotherapy SN mapping was repeated and the lymph node status was assessed with axillary lymph node dissection (ALND). SN mapping prior to chemotherapy successfully identified a mean of 2.3 SNs in all patients (IR 100%). 19 patients revealed a negative SN, 26 a positive SN (micrometastasis in 6/26). Following pCT re-SN mapping was successful in 29/45 patients (IR 64%). IR for re-mapping was 80% for patients with a primary negative SN or a micrometastatic SN compared to 45% for patients with primary macrometastatic SNs. None of the 19 patients with a negative SN biopsy and none of the 6 patients with micrometastasis prior to chemotherapy revealed positive lymph nodes following pCT. Contrary to that 15/20 patients with a macrometastasis prior to pCT revealed positive nodes following chemotherapy, and this was irrespective of the type of tumor remission due to pCT. The FNR of re-mapping was 50% and false negative SNs were only found in patients with macromatastatic SNs in the primary SN mapping. Patients with a negative SN biopsy or with a micrometastatic SN prior to pCT may forego complete ALND following pCT, whereas this may not be valid for patients with macrometastatic SNs. SN biopsy following pCT is associated with a low IR and a high FNR.