Boston, MA - The aspirin results in cancer prevention and the vitamin E results in both cancer and cardiovascular prevention from the landmark Women's Health Study (WHS) are published in the July 6, 2005 issue of the Journal of the American Medical Association.

The aspirin results in cardiovascular prevention, showing a reduction in stroke but no reduction in MI or cardiovascular death, have already been published (in March 2005 in the New England Journal of Medicine [1]). The cardiovascular results with both aspirin and vitamin E were presented and discussed (and reported by heartwire) at the American College of Cardiology meeting in March 2005.

The two-by-two factorial randomized trial, which followed nearly 40 000 healthy women for more than 10 years, showed no overall effect of aspirin or vitamin E in the primary prevention of cancer. There was, however, the suggestion of a protective effect of aspirin against lung cancer. In addition, vitamin E had no effect in the prevention of cardiovascular disease.

In the aspirin and cancer paper [2], the authors, led by Dr Nancy Cook (Brigham and Women's Hospital, Boston, MA), report that no effect of aspirin was seen on total cancer, breast cancer, colorectal cancer, or cancer of any other site, apart from lung cancer, for which there was a trend toward reduction in risk. There was also no reduction in cancer mortality, either overall or by site, except for lung-cancer mortality, which was reduced. In addition, there was no evidence of differential effects of aspirin at follow-up or interaction with vitamin E.

The researchers conclude: "Alternate-day use of low-dose aspirin (100 mg) for an average of 10 years . . . does not lower risk of total, breast, colorectal, or other site-specific cancers. A protective effect on lung cancer or a benefit of higher doses of aspirin cannot be ruled out."

In an accompanying editorial [3], Drs Eric Jacobs and Michael Thun (American Cancer Society, Atlanta, GA) say that "the totality of the evidence from laboratory studies, observational epidemiology, and randomized trials of colorectal polyp recurrence continues to support the hypothesis that moderate or high doses of aspirin may reduce the risk of colorectal cancer and possibly the risk of certain other cancers as well."

The WHS authors note, however, that whether higher doses of aspirin are effective in cancer prevention requires further trials, and the risk of gastrointestinal adverse effects must be taken into account.

In the vitamin E paper [4], researchers, led by Dr I-Min Lee (Brigham and Women's Hospital), report that 600 IU of natural-source vitamin E taken every other day provided no overall benefit for major cardiovascular events or cancer and did not affect total mortality. Cardiovascular deaths, however, were reduced in the vitamin-E group, but the authors say this observation "differs from the totality of evidence and should be explored further."

They conclude that the WHS "does not support recommending vitamin E supplementation for cardiovascular-disease or cancer prevention among healthy women." They add: "At present, in the primary prevention of cardiovascular disease and cancer, therapeutic lifestyle changes, including a healthy diet and control of major risk factors, remain important clinical and public-health strategies."

In their editorial on the cancer results [3], Jacobs and Thun point out that ongoing randomized trials will provide further information on vitamin E in cancer prevention, but they add that its promise "appears to be dimming."

In another editorial on the cardiovascular results with vitamin E [5], Dr Rita Redberg (University of California, San Francisco) says it is time to refocus attention on interventions that have been shown to provide significant benefit. "Perhaps the most important outcome of the WHS reports will be greater recognition that it is time to concentrate on teaching nutrition, promoting regular physical activity, and strongly encouraging smoking cessation," she comments.

She adds, however, that although vitamin E has been shown not to be a successful primary-prevention strategy for women, a beneficial effect in men cannot yet be ruled out. Noting that aspirin appears to provide more benefit in the primary prevention of cardiovascular disease in men than in women, she points out that more on the role of vitamin E in primary prevention will come from the Physicians' Health Study, results of which are expected in 2008.