"The study found that regular use of aspirin lowered the risk of colon cancer associated with expression of the cox-2 enzyme. This type of colon cancer accounts for about two-thirds of the colon cancer cases in the United States, according to the study. "

"However, the study authors aren't recommending that people start using aspirin for colon cancer prevention just yet. "

""Although studies have been very supportive for the potential benefit of aspirin, it still remains unclear who stands to benefit the most," said the study's lead author, Dr. Andrew Chan, an assistant professor of medicine at Massachusetts General Hospital and Harvard Medical School in Boston. "It's important to determine if there are individuals that will benefit significantly enough to outweigh the potential risks of gastrointestinal bleeding." "

"Part of the problem is that there's currently no way to know who's at risk for cox-2-expressing colon cancers, and aspirin had little effect on colon cancers that didn't express the cox-2 enzyme. That means that for about one-third of people with colon cancer, aspirin wouldn't help to prevent the disease and could cause unnecessary side effects."

"Each year, more than 140,000 Americans are diagnosed with colon cancer, and the disease claims nearly 56,000 lives annually, according to the U.S. Centers for Disease Control and Prevention. "

"Chan explained that past research had found an association between aspirin use and lower rates of colon cancer, but why aspirin might affect colon cancer rates wasn't clear. "

"To further investigate how aspirin might help to reduce the risk of colon cancer, Chan and his colleagues used data from the large Nurses Health Study and the Health Professionals Follow-Up Study. These databases had information on aspirin use and the incidence of colon cancer for almost 83,000 women and more than 47,000 men. "

"Between those databases, there were 636 cases of colon cancer with available tumor samples. The researchers found that 67 percent of the tumors had moderate or strong cox-2 expression. Cox-2 is an enzyme that causes inflammation
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