The Yield of Staging Investigations in Patients with Breast Cancer Planned for Neoadjuvant Chemotherapy

Background: Patients with breast cancer planned for neoadjuvant chemotherapy (NAC) represent a diverse population including high-risk early breast cancer (EBC) and locally advanced breast cancer (LABC). Staging investigations are routinely performed, but the clinical utility is unclear. Methods: Using a provincial cancer registry, we identified breast cancer patients referred for NAC between 2020 and 2022. Patients with staging investigations were stratified into EBC (anatomic clinical stage I–II) and LABC (stage III). Rates of metastatic (M1) disease and associated factors were assessed. Results: Among 529 EBC patients, 515 (97.4%) underwent staging. The M1 disease rate was 5.4%. The M1 rate for cT1-2N0 was 1.1%, and for cT1-2N1 it was 7.9%. In multivariable analysis, cT1N1 (OR 5.31; 95% CI 1.05–27.0; p = 0.044) and cT2N1 (OR 4.59; 95% CI 1.02–20.67; p = 0.047) were associated with M1 disease in EBC. All 320 LABC patients underwent staging. The M1 disease rate was 22.8%, significantly higher than in EBC (p < 0.001). A higher cT/N stage correlated with M1 disease in LABC, although most subgroups demonstrated rates of ≥10%. Conclusions: These findings support a risk-adapted approach to pre-treatment staging in patients planned for NAC, omitting staging in asymptomatic cT1–2N0 disease, considering it for node-positive EBC, and performing it routinely in LABC.