Clinicopathological factors associated with sentinel lymph node positivity in breast cancer using indocyanine green: a retrospective study in Peru

BACKGROUND: Sentinel lymph node biopsy (SLNB) guided by indocyanine green is an innovative technique with a high detection rate in breast cancer; however, Latin American reports are scarce. This study describes the first series of patients in Peru who underwent this technique and evaluates the relationships between clinicopathological factors and lymph node positivity. METHODS: A retrospective study was conducted on breast cancer patients who underwent SLNB guided by indocyanine green between 2021 and 2024. Clinical and pathological variables were analyzed, and their associations with lymph node positivity were evaluated via bivariate and multivariate statistical tests. RESULTS: Sixty-nine patients were analyzed, and a detection rate of 100% was achieved with the indocyanine green technique. The sensitivity, specificity, positive predictive value, and negative predictive value were 96.9% (CI: 90.8%-99.9%), 97.3% (CI: 92.1%-99.9%), 96.9% (CI: 90.8%-99.9%), and 97.3% (CI: 92.0 - 99.9%), respectively, with 95% confidence intervals (CIs). SLN positivity was significantly associated with a larger preoperative ultrasound tumor size (25.4 ± 9.0 vs. 20.7 ± 9.2 mm; p = 0.018), pT stage (65.6% vs. 37.8%; p = 0.023), and the presence of lymphovascular invasion (p < 0.001). No significant differences were found in terms of age, body mass index, menopausal status, comorbidities, laterality, or histological grade. CONCLUSIONS: Tumor size, pT stage, and lymphovascular invasion were the main predictors of lymph node positivity in this Peruvian cohort. This study constitutes the first Peruvian series evaluating indocyanine green-guided SLNB, providing relevant evidence for its implementation in Latin America and supporting its use as a safe and effective technique for the treatment of breast cancer.