Staging breast cancer by sentinel lymph node biopsy: Do patients with a single negative sentinel node (N=1) experience worse outcomes than those with multiple negative sentinel nodes (N>1)?

Background: Though sentinel lymph node biopsy (SLNB) is standard of care for early breast cancer, concern remains for false negative nodes and potential implications for understaging and undertreatment, particularly when only one sentinel node is retrieved. We examined whether patients with a single negative SLN (N =1) experience worse survival than those with two or more negative SLNs (N > 1) Methods: This retrospective review examined 730 SLN-negative patients. Clinicopathologic and demographic data, recurrence-free and overall survival were assessed. Statistical analysis included Chi square tests, Kaplan-Meier survival analysis with log-rank tests, and multivariate analysis using the Cox regression model. Results: There were no statistically significant differences in recurrence-free or overall survival between patients in the N =1 versus the N > 1 group (log rank test, p = 0.75 and p = 0.52, respectively). There were also no differences in local and distant recurrence (1.9% versus 2.1%, p = 0.89 and 2.4% versus 2.3%, p = 0.78) or breast cancer death (2.4% versus 2.7%, p = 0.85). Increased tumor size was associated with finding greater than one negative sentinel node intraoperatively (p = 0.01). Conclusions: A single negative sentinel node did not portend worse recurrence-free or overall survival. After thorough axillary exploration during SLNB, retrieval of a single negative SLN did not result in worse clinical outcomes. (C) 2018 Elsevier Ltd. All rights reserved.