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Quiz time! Aspirin is to breast-cancer recurrence as vitamin E is to ...

February 17, 2010 |  5:15 pm

Aspirin … maybe heart disease.

In light of the finding suggesting that aspirin use might decrease the risk of breast cancer recurrence and related death, it's worth recalling the limitations of such research – and previous extrapolations gone wrong.

Here’s a quick recap of Thomas Maugh's (very measured) story in today's L.A. Times: In an ongoing study of more than 4,000 women, breast cancer survivors who regularly took aspirin were 60% less likely to have a recurrence of their disease and 71% less likely to die from it.

The story goes on to explain how aspirin might affect recurrence, if it in fact does. But it also adds some perspective from Dr. John Glaspy, a breast cancer specialist at UCLA's Jonsson Comprehensive Cancer Center.

He noted that researchers -- and thus, the public -- have been misled by such findings before. As an example, he recalled previous research suggesting a connection between drinking coffee and developing lung cancer.

"The problem turned out to be that smokers drank a lot of coffee," he said. "When you controlled for smoking, everything disappeared." (I so enjoy this example.)

Full story.

Don't get me wrong -- we owe a lot to the Nurses' Health Study, from which the current findings come, and to the nurses and researchers who participate in it. (Here are a few of the study's past findings, as noted by Brigham and Women's Hospital.) Nor are we quarreling with the new results, merely some of the overstated interpretations of them. 

As the researchers would agree -- and note that they're not urging breast cancer survivors to stock up on salicylic acid -- it's risky to make health decisions based on research that asks participants a lot of questions and then looks for connections between those answers and their incidence of disease. 

A case in point: Two large cohort studies (including the Nurses Health Study) suggested several years ago that vitamin E could reduce the risk of coronary heart disease. In what shouldn't be a surprise to anyone capable of reading a headline, use of the supplement for heart patients quickly became widespread.

The L.A. Times story, Numbers can lie, explains how those findings (and similar findings) shook out:

"The therapy was finally put to the test in a Canadian randomized clinical trial of about 2,500 women and 7,000 men aged 55 years or older who were at high risk for cardiovascular events.

"The findings -- reported in 2000 -- showed that an average daily dose of 400 IU vitamin E from natural sources for about 4 1/2 years had no effect on cardiovascular disease."

-- Tami Dennis

Photo credit: Index Stock Imagery