Baby aspirin: heart helper and cancer crusader?

Patients already using low-dose aspirin (baby aspirin) to protect against cardiovascular disease may also be reducing their cancer risk, according to a new study published online in today’s The Lancet. British researchers conducted a meta-analysis of more than 25,000 people from eight clinical trials testing the efficacy of baby aspirin (81 mg dose in the U.S. and 75 mg dose in Europe) in preventing cardiovascular disease to determine if the drug also reduced the incidence of lung cancer in non-smokers and various gastrointestinal cancers. The data indicate that daily use of baby aspirin reduced overall cancer risk by an average of 21 percent while specifically reducing esophageal cancer by 64 percent, colorectal cancer by 49 percent and stomach cancer by 58 percent over a 10-20 year period. Over a 10 year follow-up period, rates of adenocarcinoma (a specific type of cancer) of the lung dropped by 30 percent among non-smokers. The researchers say that the cancer risk reduction could persist for at least 20 years.

ACSH’s Dr. Gilbert Ross notes that these findings are serendipitous, found by fortunate chance when seeking other information. “These are secondary endpoints from a meta-analysis of eight trials — the researchers were seeking information about the protective effect of low-dose aspirin on heart disease, and, in doing so, they detected an overall cancer risk reduction during the trial periods. They then decided to delve more deeply into the records for rates of various cancers among aspirin users. We don’t necessarily trust secondary endpoints due to the propensity for data dredging — finding results selectively post hoc to suit a pre-determined outcome — but the results showed highly statistically significant risk reductions spread over a group of several related cancer outcomes. These researchers happened to stumble upon the cancer reduction while analyzing the death certificates of trial participants in the course of their study of cardiovascular disease outcomes.”

So, should everyone start taking baby aspirin to prevent cancer? According to lead author Dr. Peter M. Rothwell, the risk of gastrointestinal bleeding renders use of aspirin as a chemopreventive strategy unsuitable for some patients, but “the increased risk of bleeding is about 1 in 1,000 per year, while the decreased risk of cancer is 2,3, or 4 per 1,000 per year,” he says. Dr. Ross concludes that if you are at an age “when your risk of cancer begins to increase — maybe 40 or 50 years old — and have a family history of cancer (for example, having a close relative and a distant one with cancer), you should consider consulting with your doctor about using baby aspirin to reduce your risk of cancer death.”