De-implementation of Axillary Dissection in Women With Breast Cancer is Largely Driven By Site-level Contextual Effects.

Objective: To assess the contribution of unknown institutional factors (contextual effects) in the de-implementation of cALND in women with breast cancer.

Summary Of Background Data: Women included in the National Cancer Database with invasive breast carcinoma from 2012 to 2016 that underwent upfront lumpectomy and were found to have a positive sentinel node.

Methods: A multivariable mixed effects logistic regression model with a random intercept for site was used to determine the effect of patient, tumor, and institutional variables on the risk of cALND.