A sentinel node biopsy is a method of determining whether breast cancer has spread to the lymph nodes. It is less invasive than a more extensive procedure called an axillary lymph node dissection (ALND), which involves the removal of all of the lymph nodes under the arm and may have serious side effects.
The sentinel lymph node is the first node in the body that cancer cells come in contact with as they spread or metastasize and start to move to other tissues. In breast cancer, the sentinel node is almost always located under the arm. The sentinel node acts as a gatekeeper at the entrance to the other lymph nodes. If cancer has not spread to this node, it is usually not necessary to remove the remaining lymph nodes. In turn, this spares women the potential side effects of ALND, such as swelling of the arm, numbness or pain in the upper arm and decreased shoulder mobility.
By examining the cells in the sentinel node, the surgeon can also "stage" breast cancer to determine how advanced the disease has become. This knowledge is critical in developing an appropriate treatment strategy.
If even a tiny amount of cancer is found, it is possible that other nodes have been affected and an ALND will be performed. Treatment will also include adjuvant therapy, such as radiation or chemotherapy. If the test is negative, it is almost certain that the other nodes are also tumor-free, and no further surgical treatment will be necessary. However, a woman may need to undergo chemotherapy or radiation therapy, depending on the stage of her disease.
Sentinel node biopsy usually takes about 45 minutes, longer if additional breast surgery is performed afterward, and the procedure is usually performed under light anesthesia. The technique is complicated and you should be sure to find a surgeon who has performed 30-50 such operations to ensure she has sufficient expertise to be certain of the accuracy of the technique, which determines the correct treatment.
The success rate in locating a sentinel node with this biopsy technique is 90% to 95%, while the accuracy rate in identifying the spread of cancer has been reported at 95% to 100%. You can usually return to work or resume normal activities within a few days, in contrast to the recovery period of four to six weeks following traditional ALND. Major complications from sentinel node biopsy are rare.
By Jeanne Petrek, MD, Director of the Lauder Breast Center at Memorial Sloan-Kettering Cancer Center and member, American Cancer Society's National Breast Cancer Advisory Council.
f/w o1 Updated 9/9/04
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Fall/Winter 2001
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