The beneficial effects of aspirin have been known since it was first isolated as acetylsalicylic acid from the bark of the willow tree. For eons, aspirin has been used as an antipyretic and analgesic medication. In more recent times, its utility in preventing heart attacks in patients with coronary artery disease has been well established. Researchers, lead by Dr. John Burn from Newcastle University, have reported that aspirin was able to reduce the rate of colon cancer in patients at increased risk of developing the malignancy. The results of their study were reported online in the journal The Lancet. The Colorectal Adenoma/carcinoma Prevention Programme (CAPP2) study was conducted as a randomized controlled trial comparing two daily 600 mg aspirin tablets to placebo in 861 study participants with Lynch syndrome (also known as hereditary non-polyposis colon cancer or HNPCC) . Lynch syndrome is a major form of hereditary colorectal cancer in which the affected individuals have a significantly higher predisposition to the malignancy. The investigators found 34 cases of colon cancer among the placebo group, and only 19 cases of colon cancer among the aspirin group. This was a 44% reduction in the incidence of this deadly malignancy. When the investigators analyzed the results for those study participants who took aspirin for over 2 years, there was an observed 63% reduction in the incidence of colon cancer. The authors wrote, “Despite regular colonoscopy, almost one in 14 participants not taking aspirin in CAPP2 developed colorectal cancer in less than 5 years, emphasizing the need for additional prevention strategies. Our results, taken in conjunction with recent research, provide a basis for recommendation of aspirin chemoprevention in Lynch syndrome as standard of care”. The authors also noted that future studies will need to focus on the most effective dose and duration of therapy with aspirin in patient with Lynch syndrome. In an accompanying editorial, Dr. Andrew Chan and Dr. Scott Lippman commented that “The long-term results of CAPP2 are also invaluable for the continued assessment of aspirin for prevention of sporadic colorectal cancer, which is not currently recommended mainly because of concerns about toxic effects and continuing uncertainty about dose and duration. With aspirin’s well established vascular benefits and recent evidence of benefit for colorectal and other cancers in pooled cardiovascular randomized trials, Burn and colleagues’ findings might at last tip the scales in favour of aspirin as the chemopreventive agent of choice for many individuals”. Future studies should focus on whether these results are more broadly applicable to the general population as a chemopreventive for colon cancer.
John Burn et al. “Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial” The Lancet early online publication 28 October 2011 doi:10.1016/S0140-6736(11)61049-0