# National Variation in Implementation of Sentinel Lymph Node Biopsy for Clinically Node-Positive Patients Undergoing Neoadjuvant Therapy

## TL;DR

This study examines how often doctors use a less invasive surgery to check for cancer spread in breast cancer patients after chemotherapy, finding that practices vary widely across hospitals.

## Contribution

The study reveals national trends and facility-level variation in sentinel lymph node biopsy practices for breast cancer patients following neoadjuvant chemotherapy.

## Key findings

- The proportion of patients receiving sentinel lymph node biopsy alone increased from 14% to 39% between 2012 and 2020.
- Facility-level variation in obtaining three or more sentinel lymph nodes ranged from 40% to 86%.
- There has been a decrease in completion axillary lymph node dissection, with rates dropping from 69% to 27%.

## Abstract

Sentinel lymph node biopsy (SLNB) is feasible in women with clinically node-positive breast cancer following neoadjuvant chemotherapy and a nodal pathologic complete response. Acceptable false negative rates are achieved through technical considerations such as removing three or more sentinel lymph nodes (SLNs); however, the variation that exists in adherence to this technique is unclear.

This study aimed to evaluate recent trends in axillary surgery in women with cN1-cN2 disease who received neoadjuvant chemotherapy, adherence to removing three or more SLNs, and variation in SLN yield.

We performed a cohort study using the National Cancer Database of women aged ≥18 years with cN1-cN2 disease who received neoadjuvant chemotherapy, including those without a pathologic complete response, from 2012 to 2020. Trends in axillary surgery and lymph node yield obtained during SLNB were evaluated.

The cohort included 67,365 women (median age 54 years). The number of patients receiving SLNB alone increased from 14 to 39%; SLNB with completion axillary lymph node dissection (ALND) increased from 17 to 30%; and ALND alone decreased from 69 to 27%. The rates of obtaining three or more SLNs during SLNB remained the same over time at 66%, while facility-level variation in obtaining three or more nodes ranged from 40 to 86%.

There has been de-escalation of axillary surgery with fewer patients undergoing ALND; however, overall there has been no significant change in the rates of obtaining three or more lymph nodes during SLNB following neoadjuvant chemotherapy, with significant facility-level variation observed.

The online version contains supplementary material available at 10.1245/s10434-025-17293-x.