Swollen lymph nodes are typically the only symptom directly associated with lymph node metastasis or spreading of cancer to the lymph nodes, according to the American Cancer Society. Lymph nodes that are only affected by a few cancer cells can look and feel completely normal, requiring surgical removal and laboratory analysis for cancer detection.
Lymph node swelling is also indicative of various other medical conditions or illnesses including strep throat, chickenpox and immune system disease, states the American Cancer Society. For instance, an ear infection can induce swollen lymph nodes, ear pain and fever. However, lymph node swelling can also point to specific cancers like lymphoma and leukemia, as well as metastasis of other cancers. Lymph nodes commonly swell in the underarms, neck and groin area, typically one area at a time.
Cancer found in lymph nodes directly affects cancer staging, explains American Cancer Society. Cancer that has spread to the lymph system does not always change the treatment plan. For instance, lymph nodes that are affected close to the primary tumor site may only require surgery, while additional radiation and chemotherapy is typically required for distant metastasis. The lymph system filters fluid and substances in the body and fights infection. However, this same system is capable of carrying cancer cells that have broken away from the primary tumor to other organs or areas in the body.