This is a test to look for cancer cells in one or more of your lymph nodes. The lymph nodes are small bean-shaped structures. They're part of your lymphatic system. Cancer can spread through this system to other parts of your body.
To help your surgeon find the right lymph nodes to remove, you may be injected with a radioactive fluid. This is done hours before your biopsy. You may have an injection of dye, which is done just before the lymph nodes are removed. Your surgeon will let you know what injections are right for you.
During the biopsy, you will most likely be asleep. An incision is made in your skin. Lymph nodes that have absorbed the radioactive fluid or dye are identified and removed. They are taken to a lab and examined for cancer cells. Your surgeon will follow up with you when the results are ready.