This weekâ€™s Journal of the American Medical Association (JAMA) reports on the potential benefits of aspirin following a colorectal cancer diagnosis.
Emory digestive disease expert Vincent W. Yang, MD, PhD, professor and director of the Division of Digestive Diseases, Emory School of Medicine, comments on the new study:
A large body of evidence shows that regular aspirin use can reduce the formation of colorectal cancer. Aspirin inhibits the activity of an enzyme called cyclooxygenase-2, or COX-2, that is often over-expressed in colorectal cancer.
In the Aug. 12 issue of JAMA, a study led by Andrew Chan, MD, MPH, of the Harvard Medical School, shows that regular aspirin use reduces deaths in patients who had been diagnosed with colon cancer. The study includes two large, diverse groups of individuals who were followed for more than 20 years for various health-related issues.
The individuals who developed colorectal cancer during the followâ€“up period and had used aspirin regularly had a lower death rate than those patients who developed colon cancers and did not take aspirin. More importantly, the benefit patients received from regularly using aspirin was more apparent if their cancers were positive for COX-2.
The results of this new study are consistent with the earlier finding reported in medical journals about aspirinâ€™s chemopreventive effect on colorectal cancer. However, it should be noted that this study is observational by nature and that regular aspirin use can result in significant toxicities.
To learn more about the routine use of aspirin as an adjunct treatment for colorectal cancer, studies that are blinded and randomized placebo-controlled are necessary. Such clinical trials have been conducted which proved that aspirin taken at 81 mg or 325 mg per day is effective in preventing the recurrence of colorectal adenomas (polyps) after they are removed during screening colonoscopy.
A similar clinical trial could be conducted to test the ability of aspirin to prevent colorectal cancer recurrence. Perhaps patients could first be classified based on the COX-2 levels in their tumors before being randomized into the trial. A potential outcome would be that patients with COX-2-positive tumors would receive more benefit from aspirin use than those with tumors that are COX-2-negative. Chan’s JAMA findings are a catalyst for further study.
Yang is also professor of hematology and oncology at Emory Winship Cancer Institute.