Lymph Nodes in Cancer

The lymph system is a critical component of the body’s immune system. Comprised of a complex network of organs, nodes, ducts and vessels, the lymph system generates and transports lymph – a fluid rich in white blood cells, known as lymphocytes – from tissues into the bloodstream. The key engines of the lymph system are lymph nodes – small round or bean-shaped structures that fulfill multiple roles: producing disease-fighting lymphocytes, filtering lymph of bacteria and cancer cells, and signaling infection by swelling in response to heightened levels of pathogens.

Unfortunately, the lymph system is also a common pathway for cancer to spread or metastasize to distant sites. In fact, malignant cells will often infiltrate lymph nodes as an initial step of the metastatic process. The degree of lymph node involvement is instrumental to staging cancer, establishing suitable treatment regimens and offering an appropriate prognosis. Studies in a broad range of malignancies demonstrate that the greater the extent of lymph node involvement, the poorer the likely outcome.

Intraoperative lymphatic mapping (ILM) is a procedure done during surgery and uses injected dyes or nuclear-imaging agents to identify lymph nodes that may contain metastatic disease. 

Sources

National Library of Medicine/National Institutes on Health, MedlinePlus Medical Encyclopedia, “Lymph System”. http://www.nlm.nih.gov/medlineplus/ency/article/002247.htm. Accessed 11/10/11.

Kawada, et al., “Significance and mechanism of lymph node metastasis in cancer progression”, Cancer Research 2011 Feb 15;71(4):1214-8. Epub 2011 Jan 6.

National Cancer Institute, “Cancer Staging”. http://www.cancer.gov/cancertopics/factsheet/detection/staging. Accessed 11/10/11.

De Boer, et al., “Breast cancer prognosis and occult lymph node metastases, isolated tumor cells, and Micrometastases”, Journal of the National Cancer Institute, 2010, 102 (6): 410-425

Okamoto, et al., “Number and anatomical extent of lymph node metastases in gastric cancer: Analysis using intra-lymph node injection of activated carbon particles (CH40)”, Japanese Journal of Clinical Oncology, 1999, 29 (2): 74-77

Hsu, et al., “Prediction of prognosis by the extent of lymph node involvement in squamous cell carcinoma of the thoracic esophagus”, European Journal of Cardiothoracic Surgery, 2001 Jan;19(1):10-3.