Number of nodes in sentinel lymph node biopsy for breast cancer: Are surgeons still biased?

BACKGROUND AND OBJECTIVES: The purpose of this study was to assess the number of lymph nodes removed at SLNB, and what factors might bias a surgeon's decision to remove additional nodes.

METHODS: A prospectively maintained database was reviewed. All patients that had SLNB for primary treatment of breast cancer between January 2012 and March 2016 were identified. Clinicopathologic factors were used to compare the number of LNs and rates of node positivity.

RESULTS: One thousand six hundred and three patients were included. The average number of SLNs, non-SLNs, and total LNs was 2.53, 0.54, 3.08, respectively. Significantly more LNs were removed in age <40 versus age >40 (3.73, 3.04 P < 0.01), invasive versus DCIS (3.13, 2.73 P < 0.001), Grade III versus Grade II (3.42, 2.99 P < 0.01), T2 versus T1 (3.40, 2.96 P < 0.01), and ER- versus ER+ (3.45, 3.05 P < 0.05). SLN positivity was significantly higher (P < 0.05) in invasive versus DCIS (27%, 4%), T2 versus T1 (30%. 17%), Grade II versus Grade I (42%, 18%), and ILC versus IDC (38%, 26%).

CONCLUSIONS: There was a significant difference in the number of lymph nodes removed at SLNB in certain groups however; node positivity was not necessarily higher in these groups. Surgeons must be cognizant of potential bias when performing SLNB.