For years, we have known that the vast majority of cancers spread through the lymphatic system and from there, can spread to other vital organs.
In the early 1990s, Dr. Donald Morton described a technique to identify the first lymph nodes in that sequence of spread that changed the practice of surgical oncology. In the past, patients with intermediate-risk melanoma underwent complete removal of all regional lymph nodes, a procedure that has a moderate complication rate, like lymphedema, nerve injuries and wound complications. The procedure Dr. Morton and the John Wayne Cancer Institute pioneered uses dye and radiotracers to allow the surgeon to locate and then remove these key lymph nodes, termed sentinel lymph node(s). These can then be examined under a microscope to determine if there has been any spread of the tumor outside of the primary site.
Importantly, this information provides many benefits to the patient.
- It can potentially minimize the extent of the surgery needed
- It decreases the risk for long term complications that accompany a more extensive surgery
- It provides better staging and prognostic information to help guide treatment decisions
- It has even been shown to improve patient survival
What is a Sentinel Lymph Node Biopsy?
The sentinel node biopsy procedure is minimally invasive and is done on an outpatient basis. In some cases, the larger operation may still be needed, but four out of five patients can be spared. The sentinel node biopsy technique has become the international medical standard for melanoma surgery and is being adapted to many other cancers.
The technique involves injecting a blue dye and radioisotope substance into the lymphatic system near the tumor. These tracers pass through the same pathways (lymphatic channels) that tumor cells might use and travels to the first, at-risk lymph node. This is typically done the same day as the surgery in the radiology department, where the tracer is placed in the area around the melanoma. The blue dye is injected in the operating room once the patient is under anesthesia.
Our center has state of the art detection tools to use in the operating room to accurately detect the sentinel lymph node.These intra-operative tools detect the radioactive tracers that migrate to the draining lymph nodes. These nodes also frequently turn blue from the dye that is injected.
This process usually finds one to three lymph nodes, although more could be found. These lymph nodes are then sent to pathology for examination.
Our world-class pathologists then carefully examine each lymph node for signs of melanoma cells.
If that first lymph node is clear, it means the other lymph nodes in the same area should be clear as well, and the likelihood of the melanoma recurring in lymph nodes or elsewhere in the body is markedly less. If the lymph node shows spread of melanoma, it suggests higher risks that may require more aggressive treatment.
What to Expect
Prior to the operation, you will need to get a test called a lymphoscintigram. It helps identify where the sentinel lymph node basin is. In this test, a small amount of fluid is injected into the skin around the melanoma. We also use a blue dye that is injected in the same place in the operating room. This test allows us to remove only the first draining lymph nodes, whereas in the past, we would remove all the lymph nodes in the draining basin.
Recover and Side Effects
The incision for the sentinel lymph node is small and usually only requires over the counter pain medications. There is a small risk for lymphadema, infection, bleeding or seroma formation after the procedure. However, the risks are low and it is generally a safe procedure.
If You Receive a Diagnosis of Melanoma, Your Initial Treatment Can Make All the Difference.
The Melanoma, Skin and Soft Tissue Tumors Center of Excellence at the John Wayne Cancer Institute at Providence Saint John’s is one of the most experienced centers in the world. Our physicians are comfortable selecting the best treatment option, even for unusual cases. Contact us today to schedule an appointment.