Sentinel Node Biopsy
Sentinel Node Biopsy: A Tool in the Diagnosis of Metastatic Melanoma
Jan 13, 2008
Sentinel node biopsy is a type of biopsy performed in order to see if cancer has spread to the lymph nodes. This procedure is sometimes recommended if a melanoma is found to be of moderate thickness, usually over 1mm. Before this type of biopsy was performed, all nearby lymph nodes were routinely removed and checked, in what is called a lymph node dissection. Two problems with performing lymph node dissection without having done a sentinel node biopsy first are:
- If all the lymph nodes are clear of cancerous cells, then the patient has been unnecessarily been put through an invasive surgical procedure that can have long-term complications.
- Some primary lesions are located on such an area of the body that the location of the lymph nodes that would most likely be affected by the cancer is not obvious. For example, if a melanoma were located on the right forearm, the likely lymph node basin to be checked would be the right armpit. However, if the primary melanoma were in the middle of the patient’s back, it would be difficult for the doctor to know for sure which area to check.
How Is It Performed?
- A radioactive fluid is injected into the specific area of the original lesion. This area is chosen so that the radioactive fluid will follow the same general drainage path as any suspected cancer cells.
- The patient is then x-rayed over a course of approximately two hours in order to identify the sentinel lymph node.
- Next, the patient is brought to the operating room and prepared for surgery. General anesthesia is used in most cases.
- A blue dye is then injected directly into the site of the original lesion.
- The doctor will use a handheld wand to detect the radioactive fluid while also visually following the blue dye in order to confirm the location of the sentinel node, which is the first lymph node reached by these substances.
- The sentinel lymph node is then removed and sent to the pathology lab for examination.
- The procedure is complete at this point. The incision is repaired and the patient is sent to recovery.
Benefits:
A negative result is a very good indicator that no other lymph nodes contain cancerous cells, either.
Sentinel node biopsy that comes back positive helps the doctor to know if other adjuvant therapy, such as immunotherapy or additional surgery, should be discussed with the patient.
Risks:
Sentinel node biopsy is a surgical procedure, carrying with it the risk of bleeding and infection. Pain and scarring, however minimal, are issues as well.
Suggested Reading:
Cancer Shock: Your Feelings Matter
Sources:
Sentinel Lymph Node Mapping and Selective Lymphadenectomy: The Standard of Care for Melanoma. Stanley P. L. Leong, MD, FACS.
Current Treatment Options in Oncology 2004, 5:185-194 Current Medicine Group LLC ISSN 1527-2729.
