Institutional learning curve for sentinel node biopsy at a community teaching hospital

Sentinel lymph node biopsy (SLB) is gaining popularity as an alternative to axillary lymph node dissection for breast cancer staging. Although publications have described the inherent learning curve few have analyzed actual performance in community hospitals. This study analyzes the institutional learning curve for SLB in a community teaching hospital without a formal sentinel node credentialing policy. We conducted an analysis of the initial 96 SLBs performed by 15 general surgeons over a 34-month period. The main outcomes were rate of identification of sentinel node and accuracy of SLB. Overall SLB was successful in identifying one or more sentinel nodes (mean = 2.2) in 73 per cent of attempted cases. There were marked differences in performance of individual surgeons; identification rates varied from 25 to 100 per cent. Only one surgeon performed more than 15 procedures during the study period. Nineteen of 21 cases with positive nodes were correctly characterized (sensitivity = 90.5%; 95% confidence interval = 76-100%; false negative rate = 9.5%). Our institutional learning curve was longer than high-volume individual experiences published in the literature, with a lower rate of sentinel node identification. SLB appears to be sensitive for detecting malignancy, but the small number of patients with positive nodes in our series limits our conclusions. The marked variability in individual surgeon performances and the slow rate of overall improvement in our institution suggest a need for a formalized policy for SLB training.