Triple-Tracer Sentinel Node Mapping: Maximizing Detection, Minimizing Dissection

Sentinel lymph node (SLN) biopsy often combines technetium-99m (99mTc), indocyanine green (ICG), and methylene blue (MB), but few contemporary audits quantify the performance of each tracer when used together in routine practice.

We conducted a single-center retrospective audit of 111 consecutive SLN procedures for breast cancer patients undergoing SLNB using a triple-tracer approach with technetium-99m (99mTc), indocyanine green (ICG), and methylene blue (MB). We evaluated sentinel lymph node detection rates, the number of nodes retrieved, tracer concordance, and subgroup performance (including those with mastectomy and post-neoadjuvant therapy).

Identification was 96.4% for 99mTc (107/111), 93.7% for ICG (104/111), and 78.4% for MB (87/111). Performance was heterogeneous (Q = 26.2, p < 0.001); 99mTc and ICG each outperformed MB (Holm-adjusted p < 0.001), while 99mTc and ICG did not differ significantly. Triple-tracer workflows were associated with higher odds of detection; cross-validated AUCs reached 0.98 for 99mTc and 0.82 for ICG.

Technetium remains a foundational tracer for SLNB, with ICG serving as a valuable adjunct that enhances nodal visualization and overall detection efficacy, and MB adds redundancy. Triple-tracer mapping achieved the best overall nodal identification and was associated with fewer sentinel nodes excised when complete tracer concordance was observed.