Risk of Colorectal Cancer cut by the long-term use of Aspirin
Women who take long-term anti-inflammatory drugs like Aspirin, Advil or Motrin for the treatment of diseases like arthritis may have a lower risk of developing colorectal cancer. However the beneficial effects of anti-inflammatory drugs may not become apparent until the person takes the drugs for at least a decade. It should be noted that long-term use of these drugs is associated with other health risks including gastrointestinal bleeding.
In a recently published study, Dr. Andrew Chan, and colleagues at Massachusetts General Hospital and Harvard Medical School showed that the risk of colorectal cancer is cut by as much as 53 percent by long term use of aspirin or other anti-inflammatory drugs. The reduction in risk is related to the dose taken every week and number of years the person was taking the drug.
Long-term use of aspirin and anti-inflammatory drugs do cut the risk of colorectal cancer, as per Chan, however considering the risks associated with the long term use of anti-inflammatory drugs it would not be advisable to take anti-inflammatory drugs for the purpose of prevention of colorectal cancer.
The side effects of using these drugs and the risks of colorectal cancer have to be weighed out. Colorectal cancer screening is one of the other prevention strategies and the benefits of aspirin above and beyond the current prevention needs to be examined says Dr. Chan
Eric Jacobs, a is a senior epidemiologist for the American Cancer Society says that American Cancer Society or any other group does not recommend the use of aspirin or other anti-inflammatory drugs at any dose for the prevention of cancer owing to the potential for serious side effects.
Even though advancement has been made in the screening and detection of colorectal cancer, it is still considered to be the second most deadly form of the disease. The first deadly disease is lung cancer. According the American Cancer Society, there are nearly 56,000 Americans who die due to colorectal cancer every year.
Details of the study:
Results of the study come from analysis of nearly 83,000 women aged between 30 and 55 years. These women had been providing information on the use of aspirin or other anti-inflammatory drugs. The researchers followed these women for 20 years and found that 962 women in this group developed colorectal cancer during the follow up period.
The study showed, regular users of aspirin reduced the risk of colorectal cancer by 23% when compared with women who were not taking aspirin. However these protective effects of aspirin were not apparent until after a decade of use of aspirin.
The researchers also found that more the aspirin consumed by women, the lower is their colorectal cancer risk. An eleven percent reduction in the colorectal cancer risk was found in women who took two to five aspirin tablets weekly as compared to non-users of aspirin. There was a fall in risk by 22% among the women who consumed around 6 to 14 tablets per week. On the other hand a 32 percent decrease in their risk of colorectal cancer was found in women who consumed more than 14 tablets per week. The greatest risk reduction of 53% was found in women who consumed more than 14 tablets per week for more than 10 years.
However the risk of bleeding was significantly higher in the group who were using aspirin. Risk of gastrointestinal bleeding was increased by 57% in women who were on the highest doses of aspirin.
The protective effects of were also apparent in people who take other anti-inflammatory drugs. The colorectal cancer risk was reduced by 9% in women who took two to five tablets a week of non-steroidal anti-inflammatory drugs (NSAIDs), which included Advil, Aleve and Motrin. Risk reduction was 31% in women who took six to 14 tablets per week and the risk was reduced by 46% in patients who took more than 14 NSAID doses per week. Intake of these NSAIDs were also associated with significant increase in the gastro-intestinal bleeding.
Researchers also investigated the protective effects of acetaminophen (Tylenol). Surprisingly there was no protective effect associated with this drug. Researchers believe that the protective effects of aspirin and other NSAIDs are related to their inhibition of cox-2 enzyme. Since acetaminophen does not have any action on cox-2 this may explain why acetaminophen failed to have any protective effect on colorectal cancer.
Other specific cox-2 inhibitors include vioxx and Bextra. It was recently shown that many of these drugs are associated with increased risk of serious cardiovascular diseases including myocardial infarction. Vioxx and Bextra have been recently removed from the market because of this increased risk of cardiovascular diseases associated with these drugs. However Chan's team was not able to determine if there would be similar effects due to the long-term use of over the counter NSAIDs.
Though the routine use of aspirin or NSAIDs for colorectal cancer prevention are not recommended by the researchers, these drugs may be of use to some patients, particularly those who are at a higher risk for the malignancy.
According to Dr. Chan, this study validates our understanding of the mechanism behind colorectal cancer and further avenues of research are opened.
The best way to prevent colorectal cancer according to both Chan and Jacobs is to undergo regular colorectal cancer screenings starting at the age of 50 or even earlier for those individuals who are at a higher risk for the disease.
