The first way to look for evidence of lymphatic spread is simply to carefully examine the patient, checking for swelling of the tissues and enlarged nodes. Because the lymph network nearly always follows the same pattern, your doctor will know which particular group of lymph nodes to check most thoroughly. For example, if the primary cancer is in the arm, or breast, the first lymph nodes to be affected would be those in the armpit. From there the cancer can go into the lymph nodes in the part of the neck just above the collarbone on the same side. There are lymph nodes just under the skin in the neck, arm pits, crease of the elbow, groins and back of the knee. If any of these are enlarged, they can easily be felt.

Unfortunately, there are many lymph nodes that are not so conveniently located. Chains of lymph nodes run up from the groins, just in front of the spine through the abdomen and chest. There are also groups of lymph nodes near most of the internal organs. Channels from these lead into the main chain I have described. They eventually form one large channel which empties its contents into the blood vessel just behind the inner end of the collarbone on the left. Cancer in a node at this spot can come from almost anywhere in the abdominal cavity or chest. Lymph nodes do not show up on normal X-rays. The only exception is some in the chest which, when enlarged, can be seen against the black air in the lungs. However, there are several ways of getting ‘pictures’ of the other internal glands. CT scanning is one method. This works best in chubbier people in whom the lymph nodes tend to be surrounded by fat. Because fat lets through more X-rays than the lymph nodes, it provides a contrast which allows us to ‘see’ the nodes more easily than in a thin person. In thin people the nodes lie next to muscles and blood vessels, both of which let through about the same amount of X-rays as the nodes themselves, making them very hard to ‘see’.

*93/40/1*