The outcome of selective delayed sentinel lymph node biopsy following upfront omission of axillary staging in low-risk invasive breast cancers: a retrospective hypothetical simulated analysis

TL;DR

This study explores the benefits of delaying sentinel lymph node biopsy in low-risk breast cancer patients to avoid unnecessary surgery and guide treatment decisions.

Contribution

The study introduces a hypothetical simulated analysis to evaluate the clinical and cost implications of delaying sentinel lymph node biopsy in low-risk breast cancer patients.

Findings

205 out of 712 patients were eligible for SLNB omission based on low-risk criteria.

Delayed SLNB reduced the false negative rate from 12% to 6% compared to upfront omission alone.

Adjuvant treatment rates dropped from 73% in actual practice to 27% with upfront omission.

Abstract

Sentinel lymph node biopsy (SLNB) is performed to guide recommendations on adjuvant treatments for invasive breast cancer. However, studies have shown oncological safety without SLNB in low-risk patients. We aimed to determine the clinical benefits of delaying SLNB (d-SLNB), if upfront axillary staging was omitted in patients with low-risk invasive breast cancers.

A retrospective hypothetical simulated analysis. Patients who had breast surgery and SLNB between 2019 and 2021 were included. Patients with low-risk invasive cancers were identified based on preoperative histopathology (≥ 65 years, Luminal A-like, T1, cN0, Grade 1–2). Outcome analyses were based on the Actual clinical management compared to two different hypothetical Scenarios: (A) upfront SLNB omission only, and (B) upfront SLNB omission with d-SLNB. Primary endpoints were proportion of patients suitable for SLNB omission, outcome of d-SLNB and changes in adjuvant treatments. Secondary endpoint was surgical costs.

Of 712 patients, 205 (30%) had low-risk invasive cancers and eligible for SLNB omission. In Scenario A, 25 (12%) patients with SLN metastases would have understaged. If Scenario B was applied, the false negative rate of axillary staging would reduce from 25 (12%) to 12 (6%) patients, p < 0.001. On average, adjuvant treatments were given to 73% (Actual clinical setting) vs. 27% (Scenario A) vs. 55% (Scenario B), p < 0.001. Based on 100 patients, d-SLNB was associated with an incremental cost of 55,000 EUR per 100 patients.

Although upfront SLNB omission was associated with missed SLN metastases, majority of low-risk invasive cancers were SLN negative. Delayed-SLNB could provide additional useful information to guide adjuvant treatments.

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