Research Continues to Show Sentinel Node Biopsy Effective for Determining if Breast Cancer Has Spread to Lymph Nodes (dateline January 10, 2001)
lymph node biopsy is a new procedure that involves removing only a few lymph nodes to
determine whether breast cancer has begun to spread
past the breast. Two recent studies from Ohio State University add to previous research
that shows sentinel node biopsy to be an effective method to check the status of the
axillary (armpit) lymph nodes in many breast cancer patients. The studies reveal that
sentinel node biopsy accurately determines whether breast cancer has spread to the lymph
nodes and can reduce the side effects associated with standard lymph node removal (axillary node dissection).
Both of the studies from Ohio State were presented last month at the 23rd Annual San Antonio Breast Cancer Symposium. In the first study, Emanuel Zervos, MD, a senior surgical oncology fellow at the Arthur G. James Cancer Hospital at Ohio State, and his colleagues found that removing the first one to two sentinel lymph nodes can predict whether cancer is present in the axillary region in 99% of cases. Furthermore, Dr. Zervos and his colleagues found that removing the "hottest" lymph node (that is, the lymph node that absorbed the highest amount of the radioactive tracer used to identify the nodes), also revealed whether cancer is present in the axillary region in 99% of cases.
The second study, also conducted by Dr. Zervos and his colleagues at Ohio State, compared sentinel node biopsy to standard axillary node dissection, which involves removing many or all of the armpit lymph nodes to check for cancer. The results of the study show that sentinel node biopsy reduces the occurrence of arm swelling (lymphedema) and conditions that would require a wound drain. According to Dr. Zervos and his colleagues, sentinel lymph node biopsy can help women return to work and normal activity faster than if they undergo standard axillary lymph node removal.
However, the researchers caution that not all women are candidates for sentinel lymph node biopsy, and that the 99% accuracy achieved in the first study may not apply to all facilities. Dr. Zervos said that hospitals should not routinely limit themselves to removing only the first two sentinel nodes in patients until they study their facilitys statistics regarding sentinel node biopsy. Accuracy of sentinel node biopsy is largely dependent on the skill of the surgeon and the pathologist who analyzes the removed nodes. However, when performed accurately, sentinel node biopsy can be a favorable option of lymph node removal for those who are eligible for the procedure.
Sentinel node biopsy is performed by first injecting a small dose of a low-level radioactive substance into the breast in the region of the patients tumor. This substance contains less radiation than a standard x-ray, CT scan or bone scan and is a relatively safe substance. A blue dye is also injected to help visually track the location of the sentinel node during surgery. The surgeon uses a hand held counter with a small probe attached (and sometimes nuclear medicine images) to detect the radioactive tracer and locate the sentinel node(s). Once the radioactive substance has identified the sentinel node(s), the surgeon will remove the node(s).
Because fewer lymph nodes are removed with sentinel node biopsy than standard axillary node dissection, the occurrence of side effects is usually reduced. However, possible side effects of sentinel node biopsy include post-operative pain, nerve damage, or lymphedema (arm swelling) after the procedure. The chances of these side effects increase when more lymph nodes are removed.