A sentinel lymph node biopsy is a diagnostic surgical procedure performed to determine whether cancer has spread into the lymphatic system from its original site. The sentinel node is the first node to which the cancer spreads after leaving its site of origin. In the case of breast cancer, the sentinel node is located under the arm.
Reasons for a Sentinel Lymph Node Biopsy
The two most common reasons for a sentinel lymph node biopsy to be performed are to determine whether or not a breast cancer or a melanoma has metastasized.
Sentinel node biopsy is also sometimes performed to diagnose the possible spread of certain other cancers, such as:
- Head and neck cancer
- Thyroid cancer
- Non-small cell lung cancer
- Stomach cancer
- Colon cancer
- Vulvar cancer
- Endometrial cancer
- Cervical cancer
Procedure of a Sentinel Lymph Node Biopsy
During the surgery, most often performed under local anesthesia, dye is injected to illuminate the targeted area and provide a map of adjacent lymph nodes. A special laparoscopic camera is used to photograph the lymph nodes and identify the sentinel node. Once identified, the sentinel node is removed. Slices of its tissue are sent to a laboratory for pathological testing. If tissue analysis shows that the sentinel node is free of cancer, then the cancer is very unlikely to have spread and the removal of other lymph nodes is unnecessary. If the sentinel node shows evidence of malignancy, further biopsies will have to be done to determine the extent of the spread of the cancer and to gauge appropriate treatment options.
Soreness and a small amount of bleeding normally result from the biopsy, but these symptoms almost always subside within a few days.
Complications of a Sentinel Lymph Node Biopsy
In additions to the risks common to any surgical procedure, such as excessive bleeding, blood clots, infection or breathing problems, there are a few risks particular to the biopsy procedure itself. These are not too common and, by and large, not serious. They include:
- Allergic reaction to the injected dye
- Temporary, or in rare cases, permanent, blue discoloration of skin at the site
- Fluid accumulation, or edema, at the site
- Numbness at the area of excision
In general, the sentinel lymph node biopsy is a very safe and extremely useful diagnostic procedure.