If you’ve been diagnosed with breast cancer, your surgeon will probably remove one or more lymph nodes from under your arm before or during surgery to remove the cancer. In most cases, the first step in removing the lymph node(s) is injecting a dye or radioactive tracer liquid (or both) into the area where the tumor is or under the nipple.
On March 13, 2013, the U.S. Food and Drug Administration (FDA) approved a medicine called Lymphoseek (chemical name: technetium Tc 99m tilmanocept) to help doctors find and map lymph nodes in people diagnosed with breast cancer and melanoma.
Your lymph nodes act as filters for your body’s lymphatic drainage system. So lymph nodes are likely to catch or filter out cancer cells that may be in the fluid that drains away from a cancer tumor. Knowing whether or not cancer cells are in the lymph nodes helps determine the best treatments for you.
Lymphoseek is injected around the cancer tumor. Surgeons then use a handheld radiation detector to find areas where the Lymphoseek is concentrated; these areas are lymph nodes that are draining fluid from the cancer tumor.
Still, the FDA emphasized that Lymphoseek is an imaging medicine that helps find lymph nodes, not a cancer imaging medicine.
Lymphoseek is the first new medicine approved for lymph node mapping in more than 30 years. Other medicines approved to be used for this purpose include sulfur colloid and isosulfan blue.
The FDA based its approval on two studies looking at more than 300 people diagnosed with either breast cancer or melanoma. All the participants were injected with Lymphoseek and blue dye. Surgeons later removed the lymph nodes where the dye and Lymphoseek had concentrated and examined them. All the lymph nodes that were stained with blue dye also had Lymphoseek concentrated in them. This means that the Lymphoseek was as good as the blue dye in finding tumor-draining lymph nodes. The studies also reported that a notable number of tumor-draining lymph nodes were found only by Lymphoseek. This means that the Lymphoseek was better at finding these tumor-draining nodes than the blue dye.
The most common side effects of Lymphoseek in the studies were pain or irritation at the injection site.
For more information on lymph nodes, including types of surgery to remove them, visit the Breastcancer.org Lymph Node Removal pages.