Journal: Cancer
Study question
Can sentinel lymph node biopsy (SLNB) using single blue dye alone, after neoadjuvant therapy (NAT), provide an acceptable false‑negative rate (FNR) in patients initially presenting with cN1 breast cancer?
Design
- Multicenter prospective study across 12 centers.
- Population: Adult women with cT1–4, cN1, M0 breast cancer scheduled for NAT.
- Post‑NAT procedure: Sequential single‑dye SLNB followed by completion axillary lymph node dissection in all patients.
- Primary endpoint: FNR of single‑dye SLNB in those with residual nodal disease.
Key results
- Enrollment: 432 enrolled; SLNB successful in 393 (90.97%).
- Residual disease: Pathology showed residual nodal metastases in 201/393.
- Overall FNR: 8.96% (18/201; 95% upper CI 12.02%)—within commonly accepted thresholds for post‑NAT SLNB in initially node‑positive patients.
Factors associated with lower FNR
- Age ≤60 years: 3.80% vs 27.91% for >60 (p < .0001).
- BMI <25 kg/m²: 4.20% vs 14.47% for ≥25 (p = .0151).
- Retrieval of ≥4 SLNs: 5.19% vs 16.67% for <4 (p = .0152).
- Estrogen receptor (ER)‑negative tumors: 3.52% vs 12.93% for ER‑positive (p = .0242).
- Hormone receptor–negative / HER2‑positive patients: observed FNR was 0%.
Independent predictors (multivariable)
- Higher FNR: BMI ≥25 kg/m² (OR 5.68; 95% CI 2.05–18.33; p = .0006); ER‑positive tumors (OR 3.49; 95% CI 1.15–12.72; p = .0264).
- Lower FNR: Larger number of SLNs examined (OR per additional SLN 0.65; 95% CI 0.45–0.90; p = .0088).
Clinical implications
- Feasibility: Single‑dye SLNB after NAT in initially cN1 patients can achieve a clinically acceptable FNR, even without dual tracers, in this setting.
- Best accuracy: Patients with BMI <25 kg/m², ER‑negative disease, and when ≥4 SLNs are retrieved.
- Practice impact: These data support the feasibility of single‑dye SLNB in resource‑constrained environments, with particular emphasis on maximizing SLN count and careful selection in higher‑BMI and ER‑positive patients.