The efficacy of Tilmanocept in sentinel lymph mode mapping and identification in breast cancer patients: a comparative review and meta-analysis of the ⁹⁹mTc-labeled nanocolloid human serum albumin standard of care

Abstract

Sentinel lymph node (SLN) mapping is common, however question remains as to what the ideal imaging agent is and how such an agent might provide reliable and stable localization of SLNs. (99m)Tc-labeled nanocolloid human serum albumin (Nanocoll) is the most commonly used radio-labeled colloid in Europe and remains the standard of care (SOC). It is used in conjunction with vital blue dyes (VBDs) which relies on simple lymphatic drainage for localization. Although the exact mechanism of Nanocoll SLN localization is unknown, there is general agreement that Nanocoll exhibits the optimal size distribution and radiolabeling properties of the commercially available radiolabel colloids. [(99m)Tc]Tilmanocept is a novel radiopharmaceutical designed to address these deficiencies. Our aim was to compare [(99m)Tc]Tilmanocept to Nanocoll for SLN mapping in breast cancer. Data from the Phase III clinical trials of [(99m)Tc]Tilmanocept's concordance with VBD was compared to a meta-analysis of a review of the literature to identify a (99m)Tc albumin colloid SOC. The primary endpoints were SLN localization rate and degree of localization. Six studies were used for a meta-analysis to identify the colloid-based SOC. Five studies (6,134 patients) were used to calculate the SOC localization rate of 95.91 % (CI 0.9428-0.9754) and three studies (1,380 patients) were used for the SOC SLN degree of localization of 1.6683 (CI 1.5136-1.8230). The lower bound of the confidence interval was used for comparison to Tilmanocept. Tilmanocept data included 148 patients, and pooled analysis revealed a 99.99 % (CI 0.9977-1.0000) localization rate and degree of localization of 2.16 (CI 1.964-2.3600). Tilmanocept was superior to the Nanocoll SOC for both endpoints (P < 0.0001).