Abstract P1-01-04: Tc 99m Tilmanocept and Sulfur Colloid Injection: A comparison of preoperative imaging and intraoperative lymphatic mapping of breast cancer patients – Localization rate and degree of localization
Authors: Cope FO , Metz WL , Hartman RD , Joy MT , Potter BM , Abbruzzese BC , Shuping JL , Blue MS , Christman LA , King DW 
Published: August 2014

Background: Preoperative imaging (PI) in conjunction with intraoperative lymphatic mapping (ILM) in breast cancer (BC) patients (pts) is standard for pt staging. As part of the ILM procedure, pts are evaluated post-injection (inj.) of a radiotracing agent/presurgically with PI. During ILM, the surgeon utilizes the inj. of a dye and/or a non-specific colloidal agent, such as Sulfur Colloid Injection (SCI) which may be detected intraoperatively. An ideal ILM agent such as the receptor-targeted (CD206) Tc 99m Tilmanocept provides for rapid (&lt;10 min) and tissue-specific localization in tumor draining nodes.

The objective of this evaluation of SCI and Tilmanocept was two-fold: 1) to contrast performance by assessing successful PI by post-inj. time interval and overall, and 2) to contrast localization rate and degree of localization (in vivo findings) in BC pts.

Materials/Methods: A retrospective clinical site review of SCI PI of 141 BC pts and a prospectively designed evaluation (two Phase 3 clinical trials, same clinical site) of Tilmanocept PI of 88 BC pts were completed in order to contrast post-inj time interval to successful PI (both immediate and overall). Successful immediate PI was defined as localization (hot spot identified) in &lt;10 minutes and &lt;15 minutes for Tilmanocept and SCI, respectively.

A statistical review (a meta-analysis and pooled analysis) contrasted prospective trials for Tilmanocept which included 148 (T1-4/N0/M0) BC pts with benchmarking based on regulatory documents and clinical reports of SCI. This evaluation included 963 pts from trial documented databases. Localization rate (percentage of pts with nodal localization) and degree of localization (number of nodes per pt) were determined for both SCI and Tilmanocept.

Results: After inj. of Tilmanocept, 100% (22/22 immediate; 88/88 overall) of pts demonstrated localization. After inj. of SCI, 90.1% (127/141) and 91.5% (129/141) of pts exhibited localization immediately and overall, respectively.

Localization rate and degree of localization with the benchmark for SCI, H0, are provided in Table 1 (significance is considered &lt;0.025).

Conclusions: Tilmanocept provides for both enhanced and rapid detection of lymph nodes, decreasing the time pts spend in the nuclear imaging department and improving OR throughput when employing the advantages of immediate imaging utilizing Tilmanocept over SCI. More importantly, using Tilmanocept, a receptor-targeted radiotracer, the advantages of improved localization and degree of localization of nodes may translate into additional found disease compared to non-specific agents without further dissection, decreasing pt morbidity. These data suggest that Tilmanocept may provide improved diagnostic value in ILM findings over currently approved SCI used in BC pts.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-04.