Sentinel node study

This test is to identify the normal lymphatic drainage pattern of tumour sites. It is carried out immediately prior to surgery for a malignant breast or skin tumour. 

It is known that malignant disease can travel through the lymphatic drainage channels and settle in areas away from the initial disease. For example, for many years it was common practice to carry out a removal of lymph nodes from the armpit at the same time as a mastectomy or lumpectomy in order to test all these nodes for spread of the disease. This often left patients with swollen arms due to resulting poor lymphatic drainage of the whole arm. In order to avoid this, surgeons now attempt to remove only those nodes to which the breast tissue drains. This test will identify the main (or sentinel) node to which the diseased area of the breast or other tumour site drains.

A small amount of a radioactive tracer is injected under the skin around the skin lesion or at the side of the nipple for breast disease. Images are then taken over a period of up to an hour. When the sentinel node has been identified, its position is marked on the skin surface with indelible ink.

As soon as the images have been completed, a report is prepared for the surgeon. The patient will take this straight to theatre where the surgeon can remove the sentinel node at the same time as the surgery on the main disease is carried out.