This is simply not true. Exercise has universal positive Benefits. Exercise will help to reduce side effects of treatments that can have deleterious side effects. Exercise is a non-medical type of therapy that benefits virtually all parts of the human body. Research has shown that it may also permanently alter the environment within the cancerous tumor. Brad Behnke, PhD, who is an associate professor of exercise physiology has written a very informative book on this subject. Cancer Myth #1 rebuked.