Story Created:
Sep 10, 2009
Story Updated:
Sep 10, 2009
BACKGROUND: The National Cancer Institute estimates the U.S. spends about $8.1 billion to treat women with breast cancer each year, the second-leading cause of cancer death women. Those costs go toward detection, treatment and procedures to track if treatment is working or track the cancer's spread. Biopsies -- when surgeons remove a sample of tissue -- are often performed both before and during breast cancer treatment to diagnose the condition as well as determine if additional surgery or other treatment is needed.
LYMPH NODES AND BREAST CANCER: Because of the biology of the breast, the lymph nodes are often the first place breast cancer spreads to. Each breast has blood vessels and lymph vessels. The lymph vessels carry fluid to lymph nodes, which are small bean-shaped structures found throughout the body that help fight disease and infection. The lymph nodes closest to the breast -- and therefore most susceptible to cancer -- are found under the arm, above the collarbone and in the chest.
TRACKING BREAST CANCER:To track breast cancer's spread, surgeons sometimes perform a sentinel lymph node biopsy. The sentinel lymph node is the first node to receive drainage of lymphatic fluid from a breast tumor, and also the lymph node most likely to become cancerous first. During the biopsy, surgeons traditionally inject a radioactive substance and/or blue dye near the tumor while the patient is awake, before surgery. The first lymph node to receive the substance or dye is then removed during surgery and viewed under a microscope to locate cancer.
Researchers are now testing a new radioactive substance to pinpoint sentinel nodes and better track the spread of breast cancer. Called Lymphoseek, the substance is injected while the patient is under anesthesia and binds to the receptor on lymph node white blood cells. The radioactive portion of a molecule in the substance "lights up," enabling doctors to see lymph nodes most likely to become cancerous. In a recent trial, researchers injected 46 early stage breast cancer patients with the radioactive substance and later, a blue dye. The surgeons then removed the nodes detected by the substance and had them tested for cancer. Results show more than 98 percent of the nodes detected by the blue dye were also detected by Lymphoseek. In addition, 100 percent of the nodes that tested positive for cancer were detected by Lymphoseek. Trials for Lymphoseek are now in Phase III, and the substance is also being tested in patients with melanoma.
