Surgeons may now have a better tool for tracking where tumors have spread, according to a phase III clinical trial that was reported in the Annals of Surgical Oncology. Tumors can spread into nearby (or sentinel) lymph nodes, and the new tool is a radioactive dye called tilmanocept that marks lymph nodes. The trial included 148 people with both melanoma and breast cancer. The researchers found that tilmanocept identified nearly 20% more tumor cells in sentinel lymph nodes than the standard blue dye (94% vs 76%). Tilmanocept, which is also called Lymphoseek, was approved by the FDA on March 13, 2013.