Sentinel node biopsy is a test being offered in some hospitals generally as part of a trial. It is being looked at as a way of finding out whether or not a melanoma has started to spread. When this happens, the most likely place for a melanoma to spread to is the nearest group of lymph nodes.

A tiny amount of radioactive liquid is injected into the skin around the area of the melanoma before it is removed and then the nodes are scanned to see which one has been the first to take up the radioactive liquid. During the operation a blue dye is injected into the area around the melanoma. This dye will stain the lymph nodes blue. The surgeon then removes the first lymph node that the blue fluid goes into, which is known as the sentinel node. This node is then tested to see whether it contains any melanoma cells.

If the sentinel node shows no signs of melanoma then it is very unlikely that any of the other nodes will be affected, and therefore very likely that there will be no further problems for the person concerned.

If, however, the gland does contain cancer cells then it is possible that other glands in the same area may contain melanoma cells. The surgeon will therefore probably discuss with you a further operation to remove all the lymph nodes in that area.

As with any treatment there is a risk of problems from it and a few people do develop problems with the blue dye staying in the area. Also although rare another side effect of any surgery to the lymphatic system is a build up of fluid in the area, or lymphoedema, this is due to damage to the lymph drainage. It is important to discuss this with you specialist.