[99mTc]Tc-Tilmanocept sentinel node biopsy and long-term outcomes in melanoma: A cohort study and literature review.

PURPOSE: Sentinel lymph node biopsy (SLNB) is a vital staging tool for breast cancer and melanoma with tumor lymphatic drainage commonly identified by lymphoscintigraphy (LSG) using non-specific radiopharmaceuticals. [99mTc]Tc-Tilmanocept is an FDA-approved radiotracer with specific CD206-binding with potentially improved specificity of sentinel lymph node (SLN) identification. MATERIALS & METHODS: Setting: Cohort observational study at a single UK University cancer center. We report the LSG scan time, False Negative Rate (FNR) and False Omission Rate (FOR) for SLNB stratified by two radiopharmaceuticals ([99mTc]Tc-Tilmanocept and [99mTc]Tc-Nanocolloid). Kaplan-Meier analysis compared recurrence-free survival (RFS) and melanoma-specific survival (MSS). Multivariable Cox proportional hazards regression identified independent risk factors. A literature review to identify performance of [99mTc]Tc-Tilmanocept for SLNB in any cancer type is reported. RESULTS: We identify 1058 patients (133 [99mTc]Tc-Tilmanocept and 925 [99mTc]Tc-Nanocolloid). The median Breslow thickness was higher in the [99mTc]Tc-Tilmanocept group (1.9 mm vs 1.6 mm, p = 0.01), but other cohort characteristics were similar. LSG duration was shorter with [99mTc]Tc-Tilmanocept (Median 65 vs 106min, p < 0.001). The nodal micro-metastasis rate, FNR and FOR were similar in both groups (20.3% vs 20.8%, 18.2% vs 18.3%, and 5.7% and 5.9%). The MSS and RFS were not different between the groups (HR 0.679 [95%CI 0.39-1.18] p = 0.233 and HR 0.826 [95%CI 0.558-1.22] p = 0.373). [99mTc]Tc-Tilmanocept was not an independent predictor for MSS and RFS. A literature search identified cohort studies using [99mTc]Tc-Tilmanocept SLNB for Breast Cancer, Melanoma and HNSCC, with only short-term outcomes reported. CONCLUSIONS: [99mTc]Tc-Tilmanocept reduces lymphoscintigraphy time, but with no improved specificity of SLN identification compared to [99mTc]Tc-Nanocolloid on long-term follow-up.