The lymphatic system
Lymph vessels are very fine tubes that drain the fluid, called
lymph, which escapes into the body's tissues. They run next to the arteries
and form a network that returns the watery fluid into the bloodstream
near the heart.
Lymph nodes, sometimes called glands, are swellings that occur
near to the main arteries. They act as filters for the lymph, and also
have a role in the body's immune system.
Microscopic cancer cells can escape into lymph, and can become
trapped in lymph nodes. If the cells then grow, they form growths called
metastases. This is one of the common ways that many cancers can spread
to different parts of the body.
Surgery for many types of cancer (including cervical, endometrial
and vulval cancers) usually involves removing lymph nodes and the nearby