Aspirin is a drug that's both cheap and available and it's used by millions of people, mainly to ease headache pain and counter the effects of heart disease. Now researchers have found that a daily dose may reduce the risk of many cancers and prevent tumors from spreading. Three separate studies, reported in medical journals, report that aspirin may be a powerful weapon in the fight against cancer. Andrew Chan, a gastroenterologist at Massachusetts General Hospital, is the co-author of a comment relating to the studies that appeared in journal Lancet.