The study, published last week my a multinational team of researchers in the prestigious UK journal The Lancet, followed the outcomes of five randomized trials in the UK, Sweden and the Netherlands for a period of 20 years. Over the follow-up period, after taking low doses (75mg per day) of aspirin for about 6 years, subjects had a 24% lower likelihood to be diagnosed with colon cancer, and a 35% lower likelihood to die of the disease. The use of aspirin was particularly beneficial against upper (proximal) colon cancers, which are typically not caught by colonoscopy or sigmoidoscopy. There was no advantage for larger doses than baby aspirin.
The study was particularly powerful because it had a wide patient sample (over 14,000) over three countries, and because, based on randomized trial, it was able to establish causality between the treatment and the effect.
A commentary in the same issue of the journal proposes that the daily use of a low dose of aspirin become a standard suggestion by family doctors. "Anyone with any risk factors such as a family history (of colon cancer) or a previous polyp should definitely take aspirin," said Peter Rothwell, professor at the University of Oxford, and one of the study's authors. Professor Rothwell believes that the study also "tips the balance" for anyone considering aspirin to prevent heart attacks and strokes.
Some experts cautioned patients not to start taking daily aspirin doses without consulting a doctor first, as it may cause lesions and bleeding in the stomach and intestines when taken over long periods. Low doses of aspirin in the study were 75mg, while baby aspirin doses in the US are 81 mg.
Another study about aspirin, published almost simultaneously with this one, appeared to show aspirin to have a major effect on prostate cancer treatment survival, possibly reducing death rates by 60%, with an 80% mortality reduction from high risk prostate cancers. A different study, also almost simultaneous, reported that aspirin reduces complication from heart surgery when administered immediately preceding the procedure.
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The study in The Lancet
The commentary in The Lancet