Sentinel lymph node biopsy is a very recent diagnostic procedure done on breast cancer patients in order to find out whether the cancer cells have spread to axillary lymph nodes or the lymph glands under the arm. According to studies and findings, this procedure may result in less pain and may prevent the occurrence of complications, which is common in most post-operative procedures for breast cancer.
Where can you find the sentinel lymph node?
Metastasizing breast cancer cells usually make contact with the sentinel lymph node first as they spread from the main tumor. Some forms of cancer, such as breast cancer, follow a somewhat predictable progression, reaching first a set of lymph nodes and then spreading onward to the next. Before metastasizing to other parts of the body or to other body organs, the cancer in these cases typically spread first to lymph nodes or lymph glands. The sentinel lymph node is the first of these lymph nodes to be reached by cancer cells, which have begun to metastasize.
By determining whether cancer cells found in the primary tumor has already reached the sentinel lymph node, physicians can determine what stage the cancer has progressed into. Lymph node metastasis is one of the most important bases in determining cancer stages, and it is also often used to determine which type of therapy needs to be adopted for specific types of cancer. In the case of breast cancer, if the sentinel lymph node doesn’t have cancer cells, there’s a very good probability that the cancer has not yet reached other lymph nodes or other parts of the body.
How is sentinel lymph node biopsy performed?
Sentinel lymph node biopsy is performed first by injecting a low-level radioactive tracer into the region of the patient’s breast where the tumor is located. The radioactive tracer known as technetium-99 is a safe substance that is normally injected in small doses by the surgeon prior to the operation itself. In order to determine the location of the sentinel lymph node during surgery, a blue dye is often used and injected as well. In order to detect the tracer and the sentinel lymph node, the surgeon will need to use a hand held counter.
The progress of the operation will depend on the surgeon performing the procedure; however, in most cases, the patient needs to wait for 45 minutes to 8 hours before being wheeled into the operation room for the biopsy. During the procedure, a small dose of blue dye will be injected again. At the time that the tracer and the dye have already reached the lymph nodes, the area will be scanned using a Geiger counter, which is an electrically-powered handheld gamma ray counter.
After the tracer is found and the lymph node location is confirmed, the surgeon will make an incision and surgically remove the nodes. Afterward, these nodes will be sent to a pathologist for examination and confirmation of cancer metastasis.
Advantages of sentinel lymph node biopsy
Sentinel lymph node biopsy is valuable in determining if cancer cells have already spread to the sentinel node as well as other nodes in the axilla. The procedure also helps determine the actual progression of the cancer and is used in staging and treatment. Though this type of biopsy, unnecessary dissections of lymph node are prevented. In axillary node dissections, up to 10 to 30 lymph nodes maybe removed, which may increase the chances of post-surgery complications.
Disadvantages of sentinel lymph node biopsy
Although this biopsy has been known to detect the occurrence of metastasis in the sentinel lymph nodes, there a few disadvantages to this procedure, ranging from its side-effects to the possibility of false results in detecting cancer stages.
Common side-effects of the procedure include post-operative pain and nerve damage. Although lymphedema, a common complication of needless lymph node dissections, is not an associated risk with sentinel lymph node biopsy, it can still occur if other groups of lymph nodes are extracted along with the sentinel lymph node.
The blue dye injected prior and during the biopsy procedure may also cause a discoloration of the skin. This will also make the urine appear green in color for a period of approximately 24 hours. Nonetheless, these discolorations account simply as temporary side-effects.
Another disadvantage to the procedure is the probability of obtaining a negative result, which may in fact be false. The absence of cancer cells in the sentinel node still doesn’t eliminate the possibility that cancerous cells may be lurking in the lymph node basin.
It is important, therefore, for the sentinel lymph node biopsy to be performed only by trained doctors. Not all women (or men) who have breast cancer need to undergo sentinel lymph node biopsy, however. Patients with palpable lymph nodes and advanced breast cancer and multi-focal cancer, as well as those who have already undergone radiation and surgery are poor candidates for this biopsy procedure.