The newly approved radiopharmaceutical, technetium Tc99m tilmanocept (Lymphoseek), has been shown to improve sentinel lymph node (SLN) mapping: In recent research, the agent identified more SLNs than did the current standard blue dye, with these additional SLNs enhancing the detection of clinically important nodal metastases.

A novel, engineered radioactive dye specifically designed for SLN detection, tilmanocept was approved by the FDA on March 13, 2013. “Tilmanocept advances the molecular targeting in breast cancer,” explained Anne M. Wallace, MD, chief of plastic surgery for the University of California (UC)–San Diego Health System and director of the Breast Care Unit at UC San Diego Moores Cancer Center, in a statement issued by the school. “It’s the first agent that is binding to a lymph node because it is a lymph node that plays an important role in metastasis.”

Wallace and colleagues evaluated tilmanocept in two multicenter phase 3 trials supported by Lymphoseek manufacturer Navidea Biopharmaceuticals (Dublin, Ohio). A total of 148 persons with breast cancer received injections of both tilmanocept and the current standard, vital blue dye (VBD), in the tumor area.

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A handheld radiation detector revealed that more than 99% of SLNs that had taken up the VBD also contained tilmanocept (207 of 209 nodes). No pathology-positive SLNs were detected exclusively by VBD.

As Wallace’s team reported in Annals of Surgical Oncology, tilmanocept detected a total of 320 nodes, compared to the 207 detected by VBD (64.7% of the tilmanocept-detected nodes). Nearly one-fifth of the 207 nodes (18%) were positive for cancer, and 94% of the malignancies were detected by the new radiopharmaceutical, compared to only 76% detected by VBD.

In addition, compared with VBD, tilmanocept detected at least one SLN in more study participants (146 patients vs 131 patients).

“Tilmanocept is just as accurate as current techniques, simple to use, takes less time to find lymph nodes, and is cleared faster from the body,” noted Wallace in the UC statement. “This could standardize the process of lymph node mapping and make the process easier, particularly for less experienced surgeons.”