Exercise is good for you, and being overweight increases your risk of certain types of cancer - so it's good to keep fit and to try to stay slim. But what about the situation when someone already has cancer - could exercise actually be a treatment for cancer? Researchers in Sheffield are looking at this question in men who have been diagnosed with prostate cancer. 50 men who have a diagnosis of prostate cancer confined to the prostate are being split into 2 groups. Half will have supervised exercise sessions and half will be told about the benefits of exercise but will not have direct supervision over their physical activity. The PSA blood test will be monitored to determine the impact of exercise on prostate cancer. Therein lies one of the problems of this study - PSA is an awkward (though useful) test - using it as a marker of cancer progression will be difficult.
Actually there's quite a bit of evidence already that exercise affects prostate cancer. In 2011 the "Brisk Walking Study" from San Francisco showed that men with prostate cancer who walked at least 3 miles per hour for at least 3 hours a week had a better prognosis. It could even be that exercise increases the expression of some genes that are important in combatting prostate cancer.
More data is needed, but what we know for sure, is that exercise is good for you!