Lymph Node Dissection Health Article

Definition

Lymph node dissection (lymphadenectomy) is the surgical removal of lymph nodes in order to assess the spread of cancer.

Purpose

The lymph system is the body's primary defense against infection. It consists of the spleen, tonsils, thymus, lymph nodes, lymph vessels, and the clear, slightly yellow fluid called lymph. These components produce and transport cells and proteins that help rid the body of infection.

The lymph vessels are similar to veins, only instead of carrying blood as veins do, they circulate lymph to tissues in the body. There are about 600 small, bean-shaped collections of tissue found along the lymph vessels. These are called lymph nodes. They produce cells and proteins that fight infection. They also clean and filter foreign cells, such as bacteria or cancer cells, out of the lymph.

Cancer cells can break off from the original tumor and metastasize (spread) through the lymph system to distant parts of the body, where secondary tumors are formed. The purpose of a lymph node dissection is to remove the lymph nodes that have trapped cancer cells so that the extent of spread can be determined. Lymph node dissection is done for many different types of cancers, including cancers of the head and neck, breast, prostate, testes, bladder, colon, and lung.

About 200 lymph nodes are in the head and neck and another 30 to 50 are in the armpit. More are located in the groin area. Lymph nodes are sometimes called lymph glands, although they are not true glands. When someone talks about having swollen glands, they are referring to swollen lymph nodes.

Normally lymph nodes are no larger than 0.5 in (1.3 cm) in diameter and are difficult to feel. However, when lymph nodes trap bacteria or cancer cells, they can increase in size to greater than 2.5 in (6 cm). Most often, hot and painful swollen nodes are caused by trapped bacteria. Swollen lymph nodes caused by cancer are usually painless.

Precautions

This operation usually will not be performed if the cancer has already metastasized to another site. In this case, removing the lymph nodes will not effectively contain the cancer. As with any surgery, women who are pregnant should inform their doctor before a lymph node dissection.