This section gives information about lymphoedema (pronounced limf-o-dee-ma). Lymphoedema is the swelling of an arm, leg or other part of the body because of an abnormal collection of a fluid called lymph in the body tissues.
Lymphoedema is the swelling of an arm, leg or other part of the body because of an abnormal collection of a fluid called lymph in the body tissues. This sometimes happens if cancer blocks the drainage of fluid through the lymphatic system. It can also occur when part of the lymphatic drainage system has been removed by surgery or damaged by cancer treatments such as radiotherapy.

If a lymph vessel or node becomes blocked, the lymph fluid is unable to pass along it. Because the excess tissue fluid cannot drain away normally, it builds up and causes swelling. The medical name for swelling is oedema (pronounced 'e dee ma'). When the swelling is in the lymph system, it is called lymphoedema.

Lymphoedema is not always related to cancer.

Primary lymphoedema occurs because the lymphatic system has not formed properly, but this is rare. It can also be caused by other medical conditions, which affect the lymphatic system.

Secondary lymphoedema is caused by disease or its treatment. It can occur if the lymph nodes are blocked with cancer or if they have been removed by surgery. Radiotherapy can also cause lymphoedema by creating a build up of scar tissue within the lymph nodes.

Not everyone who has radiotherapy to the lymph nodes will get lymphoedema. Lymphoedema is more likely to occur if surgery and radiotherapy are both given together to the same area - for example, when lymph nodes are removed from the armpit during surgery for breast cancer and the area is then treated with radiotherapy.