Breast cancer sentinel lymph node identification rates: the influence of radiocolloid mapping, case volume, and the place of the procedure.

Abstract

We hypothesized that high-volume surgeons performing sentinel lymph node (SLN) biopsy at an academic medical center (AMC) would have the same identification rates at suburban surgical centers (SSCs). Twenty-one surgeons performed 1199 SLN biopsies in 1187 clinically node-negative patients with an intraoperative gamma probe (IOGP) plus blue dye (at AMC) or blue dye alone (at SSCs). Demographic, radiologic, and pathological data were analyzed by generalized estimating equations logistic regression models. Four surgeons (group 1) performed 877 procedures (361, 247, 152, and 117 cases each), 426 with and 451 without IOGP. Seventeen surgeons (group 2) performed 322 procedures (2-92 cases each), 173 with and 149 without IOGP. Group 1 found 411 SLNs (96.5%) with and 419 (92.9%) without IOGP (P = .024). Group 2 found 163 (94.2%) with and 117 (78.5%) without IOGP (P < .0001). The odds of finding the SLN was 2.9 times higher with IOGP (95% confidence interval [95% CI], 1.8, 4.7; P < .001) and 2.7 times higher by group 1 than group 2 surgeons (95% CI, 1.7, 4.3; P < .001), controlling for tumor size and surgery type. High-volume surgeons identified more SLNs with IOGP (at the AMC) than without (at the SSCs). They also were more efficient than low-volume surgeons when blue dye alone was used. Low-volume surgeons were almost as efficient as high-volume surgeons when they used IOGP. Optimal identification of SLNs requires nuclear medicine facilities.