Low-dose aspirin may help prevent colorectal cancer

Jan. 6 (UPI) -- Aspirin has long been viewed as a potential lifesaver when it comes to heart attack.

Now, a study published Monday in the journal Carcinogenesis suggests the over-the-counter pain reliever may also help prevent colorectal cancer.

In experiments using mice, the authors found that a daily dose of aspirin was able to decrease tumor growth and kill off cancer cells, reducing risk for disease recurrence.

Based on their findings, "low-dose aspirin is safe and should be considered for those at risk for" colon cancer, co-author Ajay Goel, chair of the department of molecular diagnostics, therapeutics and translational Oncology at City of Hope Comprehensive Cancer Center in Duarte, Calif., told UPI.

According to Goel, he and his team will be engaged in follow-up studies to determine the appropriate dose of aspirin those at risk for disease can take as a preventative, safely, without triggering dangerous side effects such as stomach and brain bleeding.

As Goel noted, taking too much of any anti-inflammatory, including aspirin, can lead to erosion of the stomach's mucus lining, causing gastrointestinal and other problems.

For the research, Goel and his colleagues used mice and mathematical modeling to parallel the amount of daily aspirin people in the U.S. and Europe are taking in clinical trials. In all, they tested three varying daily doses of aspirin in four colorectal cancer cell lines, including tumors with micro-satellite instability and mutations in the PIK3CA gene, the latter of which has been linked with increased risk of endometrial, colon and aggressive breast cancers.

The researchers divided 432 mice into four groups: a control group, a group receiving low-dose aspirin at 15 mg per kilogram of body weight, a group receiving medium-dose aspirin at 50 mg per kilogram of body weight and a group receiving high-dose aspirin at 100 mg per kilogram of body weight, which is the mouse equivalent of 100 mg, 300 mg and 600 mg, respectively, for humans. The tumors from three mice in each treatment group were analyzed on days three, five, seven, nine and 11.

Researchers inspected "cellular apoptosis," or programmed cell death, in these tumors and found that the percentage of cells programmed to die increased in all cell lines.

Exactly how much ultimately depended on the amount of aspirin that was consumed, with the rate of cancer cell death increasing as aspirin doses increased, suggesting that the drug triggers a "domino effect" of cell death in all colorectal cell lines regardless of genetic background.

In addition, the researchers observed that low-dose aspirin was especially effective in suppressing tumor growth in animal models that had more PIK3CA genes. Overall, tumor cells in mice treated with aspirin were more likely to die and not proliferate.

To confirm their findings, the researchers applied mathematical modeling to the experimental data, measuring the rates of cell division and cell death. Next, they hope to repeat the same results in human study subjects.