Lymphoedema happens when lymph cannot flow through the body properly. Lymph builds up and causes swelling. Some swelling usually occurs after surgery but will settle down after a period. This is not the same as lymphoedema.
There are 2 types of lymphoedema.
Primary lymphoedema is a rare inherited condition in which lymph nodes and lymph vessels are absent or abnormal. This type of lymphoedema is not related to cancer treatment.
Secondary lymphoedema can occur after treatment for cancer, when lymph nodes are removed during surgery or damaged by radiotherapy. This can stop the lymph from flowing freely through the lymphatic system and can cause fluid to build up in some parts of the body. Sometimes, cancer itself can cause lymphoedema, if the tumour presses against or blocks the lymphatic system.
Lymphoedema usually develops gradually and can develop months, or even years, after your cancer treatment.