December 6th, 2010
Meta-Analysis: Daily Aspirin Reduces Cancer Deaths
A new analysis finds that long-term aspirin use reduces deaths from several common cancers. Previous studies had only shown a convincing benefit in colorectal cancer. In the new meta-analysis, appearing online in the Lancet, Peter Rothwell and colleagues combined data from more than 25,000 patients enrolled in long-term randomized trials of aspirin. They showed that patients who received aspirin had a 21% reduction in cancer deaths during the trials. The beneficial effect became apparent after 5 years of follow-up.
After long-term follow-up, based on 1634 deaths, the 20-year risk of cancer death was 20% lower in the aspirin group for all solid tumors, and 35% lower for GI tumors. For esophageal, pancreatic, brain, and lung cancers, the latent period before an effect was observed was about 5 years. The effect was more delayed for stomach, colorectal, and prostate cancers. The authors noted, however, that because aspirin treatment only lasted for 4.8 years on average, and because many patients discontinued aspirin therapy during the trials, “it is likely that we underestimated the benefit of long-term treatment on deaths due to cancer.”
The investigators observed no difference in effect based on aspirin dose, sex, or smoking status. By contrast, the absolute effect of aspirin increased with age, resulting in an absolute reduction of 7.08% in patients 65 years of age and older.
“These results do not mean that all adults should immediately start taking aspirin, but they do demonstrate major new benefits that have not previously been factored into guideline recommendations,” said Rothwell in a Lancet press release. “Previous guidelines have rightly cautioned that in healthy middle aged people the small risk of bleeding on aspirin partly offsets the benefit from prevention of strokes and heart attacks, but the reductions in deaths due to several common cancers will now alter this balance for many people.”