Aspirin May Help Risk of Specific Cancers

Dr. Robert Ashley, M.D., internist and assistant professor of medicine at the University of California gives more specific information about how aspirin may help the risk of cancer.

During the studies of aspirin and heart attacks, the first inklings of a decreased risk of cancer were shown, especially with colon cancer. These particular studies couldn’t verify the benefit of aspirin, but what we know about the drug supports the connection. Cyclo-oxygenase-2, or COX-2, is an inhibitor of aspirin. COX-2 is an enzyme important to the formation of inflammatory compounds. These prostaglandins may lead to decreased cellular replication and decreased recruitment of new blood vessels.

The Women’s Health Study that randomized 39,876 women taking a placebo or 100 milligrams of aspirin every other day was one of the earliest assessments of aspirin’s impact on cancer. For 10 years the women were followed and the majority of them had additional follow up for 7-½ more years. They found little difference in the rates of breast, lung and other cancers, but after 10 years there was a 20% reduction in the rate of colon cancer, even among those taking aspirin. The colon cancer decrease was even greater among women who continued taking aspirin in the 7-½ year follow-up. There was a 14% increase in incidents of gastrointestinal bleeding among those taking aspirin versus placebo, but no chance in death rates between the two groups from bleeding.

Two large ongoing studies are the Nurses’ Health Study and the Health Professionals Follow-Up Study. Together these studies looked at 88,084 women and 47,881 men who had been followed since the 1980s. Of those who used aspirin two or more times a week, there was a 19% reduction in colon cancer and a 15% reduction in the stomach and esophageal cancers. There was no benefit noted for any other cancers.

The decrease in colon cancer rates was significant only after 5 years of taking aspirin. Caucasians were the predominant population in both studies and may not be applicable to other races. Recently the researchers presented a follow-up to this study to the American Association for Cancer Research. The authors found a 31% decrease in the risk of colorectal cancers and reductions in breast, prostate and lung cancers. The data points to a 20% reduction in colorectal cancer risk with using aspirin regularly, but for other cancers, the numbers are not convincing.

We must all be aware, however, that there is a risk of gastrointestinal bleeding. Anyone with a history of ulcers or stomach problems with aspirin or other non-steroidal anti-inflammatory drugs known as NSAIDS in the past should not be using daily aspirin therapy. As always, consult with your provider before implemented any new health practices.

Dr Fredda Branyon