Lymphedema refers to swelling due to build-up of lymph fluid in the body. This happens when the lymph system is damaged or blocked, which can be a result of cancer treatment. During cancer surgery, lymph nodes are removed and/or radiated, and the flow of lymph fluid is impaired. 
Lymphedema is a lifelong condition, but can be well-managed when diagnosed and treated early. Symptoms may appear years after treatment, and they may appear very slowly. Sometimes it is a swollen arm or leg, and a swelling of the face (depending on the site of the cancer). Left untreated, lymphedema will increase in volume, and fibrosis or thickening of the tissues can occur. The skin will also change from spongy to hard.
This condition affects all ages and may occur years, even decades, after cancer treatment or trauma. For cancer survivors, the biggest risk of lymphedema follows treatment for breast, prostate or cervical cancer or melanoma. You can ask your healthcare provider if you are at risk, and if lymphedema should be a concern for you. 
The best evidence available indicates that exercise and weight management help in risk reduction. Physiotherapy or exercise can help the fluid move, and mild exercise will increase muscle tone while helping to maintain a healthy body weight. 
Some of the ways to treat lymphedema are physiotherapy or exercise (as mentioned above), manual lymphedema drainage applied by a specialist, compression garments or bandages, and laser therapy, among other treatments.
Lymphedema is classified according to a scale from mild to severe:
- Stage 0: There is damage to the lymph system, but there is no swelling yet. This stage might last for months or even years.
- Stage I: When pressed, the skin indents, but there is no evidence of scarring.
- Stage II: There no indentation on the skin when pressed, and there is moderate to severe scarring.
- Stage III: The skin hardens and there is much swelling of the limb that doesn’t go away. The texture of the skin changes and there is fibrosis or thickening.
It is important to avoid strenuous exercises such as running, aerobics or ball games. Take care of your skin to limit entry points for germs or infection by using a pH balanced skin moisturizer and insect repellent when outdoors. Clean and apply antibiotic cream to any cuts, scratches or grazes right away. Keep your nails and cuticles clean and cared for and protect your hands and arms when you garden or take something hot from the oven. Use high factor sunscreen and avoid sunburn. If you need to have an injection, blood work done or your blood pressure checked, inform the healthcare provider that you are at risk for lymphedema. It also helps to maintain a healthy weight and practice deep breathing and moderate exercise, ideally every day, to help get your heart rate up, blood pumping and lymph flowing. 
For more lymphedema information and resources, consult the Lymphedema Association of Ontario.