Lymphedema affects approximately 140 million people worldwide. Lymphedema is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system, which normally returns interstitial fluid to the thoracic duct and then to the bloodstream. Lymphedema can be inherited, though it is frequently caused by cancer treatments, and by parasite infections. This condition is incurable and progressive. It is treatable with manual lymph drainage or "lymphatic massage". Many cases require compression bandaging by a Certified Lymphedema Therapist.