Measuring the quality of sentinel lymph node biopsy (SLNB) for breast cancer: a population-based evaluation

Abstract

Background: The quality SLNB for breast cancer has never been evaluated on a population level. We previously developed SLNB quality indicators (QIs) and measured them at a single institution. The objective of this study was to measure SLNB quality at a population level.

Methods: Patients with a breast cancer diagnosis in Ontario who had axillary surgery between January 1 and December 31, 2005 were identified from the Ontario Cancer Registry. The cohort of patients who underwent a SLNB was determined from institutional administrative datasets and by primary chart abstraction. Data for measuring 8 QIs was abstracted. The influence of patient, provider, and institutional characteristics was determined using generalized estimating equations (GEEs) to account for patient clustering within hospitals.

Results: A total of 2323 breast cancer patients were confirmed to have undergone a SLNB. The QI measurements for SLN identification and the timing of SLNB (alongside primary tumor resection) were high, exceeding 90%. The proportion of cases associated with appropriate pathology evaluation and reporting were modest. Hospital volume of breast cases, urban or rural, and academic versus community designations did not influence quality. Younger patient age (p = .002) and number of nodes removed >1 (p =.008) were significant predictors of node positivity. Consequently, the rate of completion axillary lymph node dissection (cALND) rose with increasing metastatic burden and decreasing patient age.

Conclusions: The quality of SLNB at a population level was generally high. Further evaluation is required, particularly in determining how to improve SLNB pathology evaluation, and reporting.