Surgeon bias in sentinel lymph node dissection: Do tumor characteristics influence decision making?

Background: Determining sentinel lymph nodes (SLNs) in breast cancer staging involves subjective interpretation by the surgeon. We hypothesized patient and tumor characteristics influence number of SLNs harvested. Methods: A single-institution, prospectively collected database was queried for breast cancer patients undergoing SLN surgery (2002-2013) and mean SLN counts were compared. Results: There were 2394 SLN biopsies. Mean number of SLNs per patient for the entire cohort was 2.6. Mean number of SLNs removed was greater for patients ≤50 years (2.9 versus 2.6; p<0.0001). Fewer SLNs were removed with tumors ≤1cm (2.5 versus 2.6; p=0.002). Patients with grades 2 or 3 tumors had more SLNs removed than grade 1 (2.6 versus 2.5; p=0.03). Receipt of neoadjuvant therapy was associated with more SLNs removed (3.0 versus 2.6; p=0.005). Conclusion: Number of SLNs removed varies based on risk factors for SLN metastasis or false-negative SLN biopsy.