Comparison of [ ^99mTc]Tc-tilmanocept with [ ^99mTc]Tc-sulphur colloids and [ ^99mTc]Tc-albumin colloids for sentinel lymph node detection in patients with cutaneous malignancies of the head

Purpose: Sentinel lymph node (SLN) biopsy is a staging procedure in the management of cutaneous malignancies of the head. The ideal radiopharmaceutical is controversial. This study aimed to compare [ ^99mTc]Tc-tilmanocept (TcTM) with [ ^99mTc]Tc-sulphur colloid (TcSC) and [ ^99mTc]Tc-albumin colloid (TcAC) for SLN detection in the head and neck region. Methods: Data from 62 patients with cutaneous malignancies of the head who were injected with TcTM, TcSC, or TcAC before SLN imaging (SLN-I) and SLN excision (SLN-E) between 2012 and 2021 were retrospectively analysed. SLN-I was performed using planar lymphoscintigraphy and SPECT/CT, and a gamma probe was used for SLN-E. The SLN-I localisation rate (patients with SLNs) and degree (SLN number) and SLN-E relocalisation rate (patients with SLNs) and ratio (SLN number in SLN-E/SLN number in SLN-I) were compared between TcTM, TcSC, and TcAC. Results: TcTM showed similar SLN-I localisation rates for primaries in the anterior and posterior head region compared with TcSC (84.6% vs. 72.4%, p=0.680; both 100.0%) and TcAC (84.6% vs. 75.0%, p=1.000; both 100.0%). The SLN-I localisation degree for TcTM was higher for primaries in the anterior head region and similar for primaries in the posterior head region compared with TcSC (3.2 vs. 2.3, p=0.034; and 1.8 vs. 2.2, p=0.506) and TcAC (3.2 vs. 2.0, p=0.038; and 1.8 vs. 2.7, p=0.329). The SLN-E relocalisation rates and ratios were similar for all. Conclusion: On the basis of a limited study design that compared three different tracers in three different patient groups, TcTM showed comparable overall performance to TcSC and TcAC.