Lymphedema is swelling, usually in the arms or legs, but also in other parts of the body, that is caused by the removal of or damage to lymph nodes during treatment of cancer. It's caused by lymphatic fluid becoming clogged up when the regular pathways are no longer available. Lymphedema that occurs as a result of surgery or other cancer treatment is classified as "secondary", as opposed to lymphedema that occurs naturally as a result of a naturally-occurring malfunction of the lymph system. It can present itself immediately after treatment, or weeks, months, even years after the trauma that caused it.
Here's a description from The National Lymphedema Network:
Secondary lymphedema, or acquired lymphedema, can develop as a result of surgery, radiation, infection or trauma. Specific surgeries, such as surgery for melanoma or breast, gynecological, head and neck, prostate or testicular, bladder or colon cancer, all of which currently require removal of lymph nodes, put patients at risk of developing secondary lymphedema. If lymph nodes are removed, there is always a risk of developing lymphedema.
Lymphedema can develop in any part of the body or limb(s). Signs or symptoms of lymphedema to watch out for include: a full sensation in the limb(s), skin feeling tight, decreased flexibility in the hand, wrist or ankle, difficulty fitting into clothing in one specific area, or ring/wristwatch/bracelet tightness. If you notice persistent swelling, it is very important that you seek immediate medical advice (and get at least one second opinion) as early diagnosis and treatment improves both the prognosis and the condition.The current treatment plans for lymphedema vary depending on the cause and location, and whether or not treatment is still occurring. If you notice any of the signs listed above in yourself or your loved one, contact your oncologist or surgeon immediately to report them, and schedule a visit to talk about the best way to manage it based on your personal health.