Lymph nodes are part of the lymph system, a network of organs, nodes, ducts, and vessels that support the body's immune system.
Nodes are little filters throughout the body. The cells in lymph nodes help to destroy infection, such as from a virus, or harmful cells, such as cancer cells.
Cancer can spread or start in lymph nodes.
How Cancer Gets in the Lymph Nodes
Cancer can start in the lymph nodes. This is called lymphoma. There are several types of lymphomas, such as non-Hodgkin lymphoma.
Cancer cells can also spread to the lymph nodes from a cancer in any part of the body. This is called metastatic cancer. Cancer cells break off from a tumor in the body and travel to an area of lymph nodes. The cancer cells often travel to nodes near the tumor first.
How Cancer in Lymph Nodes is Found
Nodes swell as they work hard to fight cancer cells.
You or your health care provider may feel or see swollen lymph nodes if they are close to the surface of the skin, such as in the neck, groin, or underarms.
Keep in mind that many other things also can cause lymph nodes to swell. So having swollen lymph nodes does not mean you definitely have cancer.
When a provider suspects that cancer cells may be present in lymph nodes, certain tests may be performed to detect cancer, such as:
What it Means When Cancer is Found
A node can have a small or large amount of cancer cells in it. There are hundreds of nodes throughout the body. Several clusters or only a few nodes may be affected. Nodes near or far from the primary tumor may be affected.
The location, amount of swelling, number of cancer cells, and number of nodes affected will help determine the treatment plan. When cancer has spread to lymph nodes, it is in a more advanced stage.
The cancer in lymph nodes can be treated with:
Removing Lymph Nodes
Surgical removal of lymph nodes is called lymphadenectomy. Surgery can help to get rid of the cancer before spreading further.
After nodes are removed, fluid has fewer places to go. Sometimes back up of lymph fluid, or lymphedema, can occur.
When to Call the Doctor
Call your provider if you have questions or concerns about swollen lymph nodes or your cancer treatment.
Camp MS, Smith BL. Lymphatic mapping and sentinel lymphadenectomy. In: Cameron JL, Cameron AM, eds. Current Surgical Therapy. 11th ed. Philadelphia, PA: Elsevier Saunders; 2014:592-595.
Hall JE. The microcirculation and lymphatic system. In: Hall JE, ed. Guyton and Hall Textbook of Medical Physiology. 13th ed. Philadelphia, PA: Elsevier; 2016:chap 16.
Padera TP, Meijer EF, Munn LL. The lymphatic system in disease processes and cancer progression. Annu Rev Biomed Eng. 2016;18:125-158. PMID: 26863922 www.ncbi.nlm.nih.gov/pubmed/26863922.
Review Date 8/15/2016
Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.