An Aspirin a Day Lowers Cancer Mortality

August 10, 2012 — Results from a new study support the daily use aspirin to help prevent death from cancer.

However, questions remain about the size of the potential benefit, lead author Eric J. Jacobs, MD, from the American Cancer Society (ACS) in Atlanta, Georgia, told Medscape Medical News.

"We were prompted to do the study because a recent analysis pooling results from existing randomized trials of daily aspirin for the prevention of vascular events found an estimated 37% reduction in cancer mortality among those using aspirin for 5 years or more [Lancet. 2012;379:1602–1612]," Dr. Jacobs said.


"But uncertainty remains about how much daily aspirin use may lower cancer mortality. The size of this pooled analysis was limited, and 2 very large randomized trials of aspirin taken every other day found no effect on overall cancer mortality," he explained.

To clarify how much daily aspirin use might lower the risk for fatal cancer, Dr. Jacobs and his colleagues analyzed information from 100,139 predominantly elderly participants in the Cancer Prevention Study II Nutrition Cohort who reported using aspirin on questionnaires.

The study was published online August 10 in the Journal of the National Cancer Institute.

The participants, who did not have cancer at the start of the study, were followed for up to 11 years.

The researchers found that daily aspirin use was associated with an estimated 16% lower overall risk for cancer mortality, both among people who reported taking aspirin daily for at least 5 years and among those who reported shorter-term daily use.

The reduction in overall cancer mortality was driven by a decrease of about 40% for cancers of the gastrointestinal tract (such as esophageal, stomach, and colorectal cancer) and a decrease of about 12% for cancers outside the gastrointestinal tract.


Too Soon to Recommend Aspirin to Prevent Cancer

"Although recent evidence about aspirin use and cancer is encouraging, it is still premature to recommend that people start taking aspirin specifically to prevent cancer," Dr. Jacobs said.
"Even low-dose aspirin can substantially increase the risk of serious gastrointestinal bleeding. Decisions about aspirin use should be made by balancing the risks against the benefits in the context of each individual's medical history, and any decision should be made only in consultation with a healthcare professional," he explained.

He added that expert committees developing clinical guidelines will consider the totality of the evidence on risks and benefits when guidelines for aspirin use are updated.
"I hope this study and other recent promising research about aspirin will lead to studies that look very carefully at daily aspirin use over long periods of time to more clearly understand aspirin's effects on specific cancers," Dr. Jacobs said.

Big Picture Is Positive
In an accompanying editorial, John A. Baron, MD, from the University of North Carolina School of Medicine in Chapel Hill, writes that "overall, the well-conducted ACS study is an echo of other data on aspirin and cancer mortality, not a resounding confirmation."

The "big picture" on aspirin use and cancer is "very positive," he noted. "The drug clearly reduces the incidence and mortality from luminal gastrointestinal cancers, and it may similarly affect other cancers. This is exciting: simply taking a pill can prevent cancer incidence and cancer death."

However, like Dr. Jacobs, Dr. Baron urges caution with regard to the widespread recommendation to use aspirin to prevent cancer.

Just because aspirin is effective "does not mean it necessarily should be used. Aspirin is a real drug, with definite toxicity. As for any preventive intervention, the benefits must be balanced against the risks, particularly when the benefits are delayed whereas the risks are not," he writes.
Dr. Jacobs has disclosed no relevant financial relationships. Dr. Baron reports being a consultant to Bayer, and holding a use patent for the chemopreventative use of aspirin, currently not licensed.
 
J Natl Cancer Inst. Published online August 10, 2012
 http://www.medscape.com/viewarticle/768917?src=nldne