Sentinel lymph node biopsy after neo-adjuvant chemotherapy in breast cancer

The timing of sentinel node biopsy in the setting of neo-adjuvant chemotherapy for breast cancer is controversial. Sentinel node biopsy performed after neo-adjuvant chemotherapy may save patients with a nodal response the morbidity of an axillary lymph node dissection. A retrospective review of prospectively collected data compared sentinel node biopsies performed after patients had received neo-adjuvant chemotherapy with patients who had not received neo-adjuvant chemotherapy. Demographic factors, tumor characteristics, and the results of the sentinel node biopsies and completion lymph node dissections (when applicable) were compared. A total of 231 axillary procedures (224 patients) were evaluated. The patients who received neo-adjuvant chemotherapy (NEO; N=52) were younger, had higher grade tumors, were more likely to have a mastectomy, and were more likely to have ER-negative and HER-2/neu positive tumors than the patients who did not receive neo-adjuvant chemotherapy (NON; N=179). The mean clinical tumor size in the neo-adjuvant group was 4.5cm (±1.8) prior to chemotherapy; the post-chemotherapy pathologic size was 1.4cm (±1.3). A sentinel node was identified in all cases. There were no significant differences between the groups in the mean number of sentinel nodes removed (NEO=3.3; NON=3.1; p=0.545), the percentage of positive axillae (NEO=24%; NON=21%; p=0.776) or the mean number of positive sentinel nodes (NEO=1.3; NON=1.5; p=0.627). There was no difference in the percentage of completion lymph node dissections with additional positive nodes (NEO=20%; NON=35%; p=0.462); there was a difference in the number of nodes removed in the completion lymph node dissections (mean NEO=12.0; NON=16.4; p=0.047). Sentinel node biopsy performed after neo-adjuvant chemotherapy appears to be an oncologically sound procedure and may save some patients the morbidity of a complete lymph node dissection.