Aspirin appears to lower colon cancer risk among people with high levels of a specific type of gene, according to data from the Nurses Health Study and Health Professionals Follow-up Study.
The finding comes from a multi-institutional team that analyzed data and other material from two long-term studies involving nearly 128,000 participants. The researchers found that individuals whose colons have high levels of 15-hydroxyprostaglandin dehydrogenase RNA dramatically reduce their chances of developing colorectal cancer by taking aspirin. In contrast, the analgesic provides no benefit to individuals whose colons show low levels of 15-PGDH.
While previous trials and prospective studies had indicated aspirin could reduce colorectal cancer risk, this retrospective study, published in the April 23 issue of Science Translational Medicine, is described as the first to indicate why aspirin benefits only some people.
The research team included representatives from Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, Cleveland; and Dana Farber Cancer Institute, Harvard School of Public Health, Brigham and Womens Hospital and Massachusetts General Hospital, Boston.
If you looked at the folks from the study who had high 15-PGDH levels and took aspirin, they cut their risk of colon cancer by half, senior author Sanford Markowitz, MD, PhD, professor of cancer genetics at Case Western, said in a news release. If you looked at the folks from the study that were low for 15-PGDH, they did not benefit at all from taking aspirin. These findings represent a clean yes-no about who would benefit from aspirin.
According to the American Cancer Society, colorectal cancer is the second leading cause of cancer-related deaths in the U.S., with projections that 137,000 Americans will develop the disease and 50,000 will die from it in 2014. Thanks to regular screenings, the death rate from colorectal cancer has dropped in the past 20 years, and members of this research team have been dedicated to finding additional measures to help reduce risk and ultimately eradicate the disease.
In this latest effort, the researchers examined tissues of 270 colon cancer patients culled from 127,865 participants followed for over three decades in the Nurses Health Study and Health Professionals Follow-up Study.
The study is among the first examples of the type of test that could allow more personalized decisions about treatment to prevent colorectal cancer, the researchers noted. It also allows those whose 15-PGDH levels indicate aspirin would have little impact to avoid the potential gastrointestinal challenges such as stomach ulcers that can accompany aspirin use.
The researchers next steps are to develop a cost-effective and accessible test for measuring 15-PGDH in the colon and to conduct a prospective clinical trial to further confirm these findings.
The mechanisms of action in the 15-PGDH gene and in aspirin make them key players in the colon cancer discussion, the researchers noted. Prostaglandins promote development of colon cancer, and aspirin helps prevent colon cancer development by preventing prostaglandins from being generated; 15-PGDH also helps prevent colon cancer development by catalyzing a chemical reaction that can negate prostaglandins.
Markowitz refers to 15-PGDH as the bodys genetic form of aspirin. The study shows that both aspirin and 15-PGDH must work together to effectively prevent colon cancer.
Study abstract: http://stm.sciencemag.org/content/6/233/233re2.abstract