Sentinel lymph node mapping of breast cancer via intradermal administration of Lymphoseek

Lymphoseek is a molecular imaging agent specifically designed for sentinel lymph node (SLN) mapping. We conducted a Phase I trial which measured the injection site clearance and SLN accumulation after a single intra dermal injection of Lymphoseek or [99mTc]sulfur colloid protocol. Ten patients with breast cancer participated in this study. Five patients received an intradermal administration of 1.0 nmol of 99mTc-labeled Lymphoseek and five patients received an intradermal administration of filtered [99mTc]sulfur colloid (fTcSC). Lymphoseek exhibited a significantly (P<.001) faster injection site clearance than fTcSC. The mean Lymphoseek clearance half-time was 2.61±0.72 h compared to 24.1±17.7 h for fTcSC. The mean SLN uptake of Lymphoseek (1.1±.5%) and fTcSC (2.5±4.9%) was statistically equivalent (P=.28). When an intra dermal injection was employed, Lymphoseek demonstrated faster injection site clearance than fTcSC.