At present, damage to the gut is one of the factors that limits the intensity of radiotherapy and chemotherapy treatments.

BBC: Minimising cancer care damage

"I think that's the thing people don't understand -- the heightened intensity does damage to your body, immune system, energy levels, on the fitness of your muscles, ligaments, tendons, " Gimelstob said.

CNN: Should tennis be worried about the 'kissing disease'?