Can a Pill Prevent Cancer?

It's an attractive idea—taking a pill to prevent cancer. Researchers have long chased this idea, studying whether anti-inflammatory drugs could prevent cancer and a host of other illnesses. A group of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs), which includes aspirin, ibuprofen and naproxen, have received perhaps the most study.

NSAIDs are used to relieve pain, often from headaches and arthritis, but also to reduce inflammation and fever. These drugs inhibit enzymes called COX (cyclooxygenase) 1 and 2, which trigger inflammation. Precancerous tissues also produce these enzymes.

Because inhibiting COX enzymes stalls inflammation and thus could help prevent or treat cancer, researchers have looked at long-term NSAID use as one tool in the fight. Aspirin in particular has been studied and shown promise in several tumor types, including breast, colon, esophageal and stomach cancers. One of the most recent studies, published in 2013 in the journal Cancer, examined whether taking NSAIDs could cut melanoma risk. After looking at data from approximately 60,000 women, researchers found that those who took aspirin had a 21 percent lower risk of melanoma compared with those who didn’t. Taking other NSAIDs resulted in no difference in risk. However, like most of the research into anti-inflammatories, this study was observational (rather than a gold-standard clinical trial) and therefore didn’t provide strong enough evidence to recommend regular NSAID use.

So far, only one NSAID has approval from the Food and Drug Administration for cancer prevention. Celebrex (celecoxib) was OK’d to reduce polyp formation in people with familial adenomatous polyposis (FAP), a condition that increases the risk of a person developing colorectal cancer at an early age.

Another factor to consider: Long-term use of NSAIDs carries the risk of serious side effects, most notably stomach bleeding and kidney damage. In fact, the U.S. Preventive Services Task Force counsels against routinely using aspirin or other NSAIDs to prevent colorectal cancer in people with average risk of getting the disease.