Validating the performance of the mammary sentinel lymph node team.

BACKGROUND AND OBJECTIVES: The mammary sentinel lymph node (SLN) procedure has the potential to improve the accuracy and lower the morbidity of axillary staging in breast cancer patients, but results are closely linked to experience and can vary widely between institutions. Standardized performance measures need to be established in order to optimize the transition to SLN biopsy only.
METHODS: Performance data were prospectively collected for the first 156 mammary SLN procedures performed by three surgeons in our institution.
RESULTS: Seventy-five cases were required to achieve an SLN visualization rate of > 80% on preoperative lymphoscintigraphy. The SLN visualization rate was 90% for the last 52 cases. Two surgeons required 25 cases before consistently achieving a > or = 90% SLN identification rate in the operating room and one required 15 cases. The metastasis detection rate increased from 22% for the first 52 cases to 31% for the last 52 cases. The false negative rate for the procedure was 5%.
CONCLUSIONS: The following performance criteria and benchmarks are suggested for validating the performance of the SLN team: (1) SLN visualization rate on preoperative lymphoscintigraphy > or = 80%, (2) SLN identification rate in the operating room > or = 90%, (3) False negative rate for the procedure 5%. Thirty procedures per surgeon were sufficient to achieve these benchmarks in our group.