NEW YORK (Reuters Health) - Men who routinely take aspirin seem to be less likely to develop colorectal cancer, according to new research findings. However, the benefit requires the dose of aspirin to be higher than usually recommended for heart health, and to be taken over at least 6 years.
“Long-term data on the risk of colorectal cancer according to dose, duration, and consistency of aspirin therapy are limited,” Dr. Andrew T. Chan, of Massachusetts General Hospital, Boston, and colleagues write in the medical journal Gastroenterology.
The research team collected data on aspirin use and cancer risk factors every 2 years among more than 47,000 men between 40 and 87 years old at enrollment in the Health Professionals Follow-up Study in 1986. .
During 18 years of follow-up, 975 cases of colorectal cancer were documented.
After adjustment for risk factors, men who reported taking aspirin regularly (at least twice a week) had a 21 percent lower risk of developing colorectal cancer compared with men who were not regular aspirin users.
However, men who had been taking aspirin regularly for five years or less did not have lower odds of colorectal cancer. Similarly, after stopping aspirin, the reduction in risk was no longer evident four years later.
The benefit associated with aspirin use was related to the dose of aspirin. Men who took the equivalent of up to one-and-half standard 325-milligram tablets of aspirin per week did not have a significantly lower risk of colorectal cancer, the researchers report.
On the other hand, those who took 6 to 14 standard aspirin tablets per week had a 28 percent reduction in risk of colorectal cancer, and those taking more than 14 tablets per week had a 70 percent reduction.
The next step, the researchers say, should be to investigate the potential risks and benefits, along with what the optimal dose should be.
SOURCE: Gastroenterology, January 2008.