The sentinel lymph node is the first lymph node or nodes to which your melanoma could spread.
By removing the sentinel lymph node, we can find out whether your melanoma has spread to the lymph nodes. This is important information so we can advise you of the correct stage and prognosis of your melanoma.
The sentinel lymph node biopsy is usually performed at the same time as the wide local excision (WLE) of your melanoma.
Lymph nodes filter bacteria and cancer cells from tissue fluid. Groups of lymph nodes are found in the neck, axilla (armpit), groin, chest and abdomen.
Before surgery a small amount of radioactive fluid is injected around the site of the melanoma biopsy scar. A special scan locates the likely position of the sentinel node(s). The position of the node will be marked on your skin.
Just before the operation a small amount of blue dye will also be injected around the biopsy scar.
Your surgeon uses a radiation detection probe and the presence of blue dye in the lymphatics to locate the sentinel node.
Removal of the sentinel node requires a general anaesthetic.
Occasionally, despite the scan and blue dye, no lymph node can be found.
Possible complications include bleeding, infection, wound healing problems and scarring. Sometime the armpit or groin region can feel a little stiff for a while.
Removal of the lymph nodes can cause a build up of fluid at the site of the wound (a seroma). There is a very small chance of fluid build up affecting the entire limb (lymphedema).
1% of people have an allergic reaction to the blue dye. Should this happen your anesthetist and theatre team are trained to deal with this.
The blue dye will dis-colour your urine for a few days. Please don’t be alarmed – it is temporary.
The pathologist examines the node under the microscope. The results take 1-2 weeks to become available.
If melanoma cells are found within the sentinel node the result is considered positive. This means you have stage 3 melanoma.
Your surgeon will discuss the results with you and your family. Commonly you will be offered a further operation to remove the remainder of the lymph nodes in that area. This second operation is called a completion lymphadenectomy or lymph node dissection.