Risk Stratification for Sentinel Lymph Node Positivity in Older Women With Early-Stage Estrogen...

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• Current guidelines suggest omitting sentinel lymph node biopsy (SLNB) for select older patients with early-stage, ER+/HER2- invasive breast cancer.
• Despite recommendations, many eligible women still undergo SLNB, indicating a need to refine deimplementation strategies.

Purpose of the Study:

• To stratify patients aged 70 years and older with early-stage ER+/HER2- invasive breast cancer into risk cohorts for nodal positivity.
• To develop predictive models for nodal positivity to guide deimplementation of low-value SLNB procedures.

Main Methods:

• Retrospective cohort analysis of 68,867 patients from the National Cancer Database (2018-2021).
• Exclusion of patients who received neoadjuvant therapies.
• Recursive partitioning analysis (RPA) to create clinical and pathologic models for nodal positivity prediction.

Main Results:

• Overall, 13.4% of patients who received SLNB had tumor-involved lymph nodes.
• Clinical model: <8% risk of nodal positivity for T1mi-T1b, grade 1-2 tumors.
• Pathologic model: <10% risk for pT1 tumors without lymphovascular invasion (LVI); <5% risk for T2 tumors without LVI and nonductal/nonlobular histology.

Conclusions:

• Patients aged 70+ with early-stage ER+/HER2- invasive breast cancer, particularly those with T1 tumors, exhibit a low risk of nodal positivity.
• RPA-defined subgroups provide a novel tool to predict nodal positivity, supporting deimplementation of unnecessary axillary surgery.