Abstract

Purpose
Sentinel lymph node biopsy (SLNB) using dye and isotope (DUAL) is recommended over the dye-only (DYE) method after neoadjuvant chemotherapy (NCT) due to potentially lower false-negative rates. However, the long-term outcome of either method is unclear. We aimed to compare the long-term oncological outcomes of DYE versus DUAL SLNB methods in patients who received NCT.
Materials and Methods
In this retrospective cohort study, 893 patients who underwent SLNB following NCT and had pathologically negative lymph nodes were included. After propensity score matching for cT, cN, and pT stages, 280 patients were in the DYE group and 560 in the DUAL group. Indigo carmine was used for dye and Tc-99m antimony trisulfate for isotope mapping.
Results
Median follow-up was 75.6 months in the DYE group and 83.0 months in the DUAL group. Mean (±SD) number of harvested sentinel nodes was 6.7 (±3.4) and 6.7 (±3.8) in the DYE and DUAL groups (p=0.51). Five-year distant metastasis-free survival was 95.2% in DYE group and 93.3% in DUAL group (HR=1.45; 95% CI, 0.82–2.57; p=0.19). Disease-free survival (HR=0.97; 95% CI, 0.69–1.50; p=0.91) and overall survival (HR=0.98; 95% CI, 0.56–1.69; p=0.95) were not significantly different. Axillary recurrence rate was 1.8% and 2.5% in DYE and DUAL groups(p=0.64).
Conclusion
Long-term oncological outcomes did not significantly differ between DYE and DUAL SLNB methods. The dye-only method can be safely recommended for breast cancer patients who received NCT.

• Keywords: Breast neoplasms, Sentinel lymph node mapping, Dye-only method, Oncologic outcome