Aspirin & cancer story: what’s right dose of caveats?

Posted By


When TV networks lead with a health care study – as NBC did last night – my antenna are up looking for caveats.  NBC anchorman Brian Williams opened like this:

“We are going to begin here tonight with a story from the world of medicine that could end up affecting every American. This is a story about cancer, its treatment and prevention, and this time it’s a story about aspirin. It is without question the cheapest medication in the American household. Its role in preventing heart disease and strokes is well documented.  We call it the wonder drug. But this is about something else. It’s new evidence tonight having to do with the role aspirin plays in preventing certain kinds of cancers.”

Framing…emphasis…elements put into a story and left out.

HealthDay put up high in its story:

But the research is not conclusive and did not prove that aspirin combats cancer.

And HealthDay later reported:

While the study is attention-getting, not everyone agrees with the overall conclusions.

Among them is Nancy R. Cook, an associate biostatistician at Brigham and Women’s Hospital and Harvard Medical School in Boston and co-author of an accompanying journal editorial. She pointed out that these studies only dealt with trials where aspirin was given daily, whereas two large trials in which aspirin was given every other day found no connection with cancer prevention.

“Aspirin seems to work for people who have had cardiovascular disease. Perhaps in the long-term it will turn out to be protective for cancer, but we need to verify that and get more information,” Cook said.

The Reuters London story went out of its way to point out that aspirin was originally developed by Bayer, but didn’t note, as MedPage Today did, that:

(one author) disclosed relationships with AstraZeneca, Bayer, Boehringer Ingelheim, sanofi-aventis, Bristol-Myers Squibb, and Servier. Co-authors disclosed relationships with AstraZeneca, Bayer, sanofi-aventis, and Bristol-Myers Squibb.

The MedPage Today story also added this context:

Despite the comprehensive nature of the analyses, they did not include the two largest clinical evaluations of aspirin’s effect on cancer risk, noted authors of a commentary published simultaneously in The Lancet. The Women’s Health Initiative and the Physicians’ Health Study involved more than 60,000 men and women, and neither demonstrated an effect of aspirin on cancer risk.

Physician-blogger Marya Zilberberg dug deeper in her post, “Aspirin or bias?,” praising a Cancer Research UK blog review:

“…of the new and old aspirin data with respect to its effects on cancer and cardiovascular complications in the context of a heightened risk for bleeding. The review is full of fabulous information about what we know and the uncertainties that remain, all with practical suggestions at the end.”

But she also points to a possible selection bias:

“…(which) may very well mean that aspirin’s role is not as a cancer prevention, but more likely as a sort of a stress test for those with a subclinical cancer. So we are left again with the the chicken-and-egg question. But isn’t that, after all, what makes science exciting?”

I encourage you to read her analysis.

Addendum on March 22:  Another noteworthy post – “The Lancet and aspirin and all cause mortality,” by Margaret McCartney.

You might also like


Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.

Joy Simha

March 21, 2012 at 10:28 am

Thank you Gary for always bringing the whole story to our attention!

Gregory D. Pawelski

March 21, 2012 at 12:58 pm

Dr. Robert Nagourney, medical director at Rational Therapeutics, pointed out on his blog last November that while most patients develop colorectal cancer over a period of decades, associated with an accumulation of genetic mutations, a small percentage of patients have a genetic predisposition for this cancer. Among these are those people that carry the familial adenomatous polyp syndrome (FAPS) and those who carry mismatch repair mutations known as Lynch syndrome.

It is the latter group who were the subject of a report in the October 2011 issue of the journal Lancet. In this study of 861 patients, known as the CAPP2 trial, patients with Lynch syndrome received either placebo or 600mg of aspirin per day. The results revealed a statistically significant reduction of colon cancer that clearly favored the aspirin group. To put this in perspective, this dramatic improvement in the highest risk population didn’t come about as the result of a new signal transduction inhibitor or a monoclonal antibody. Instead, it came from the simple administration of one of mankind’s earliest medicinal substances.

What was most laudatory was that the intervention, while highly effective, was so inexpensive. In an era of proprietary medications and the promotion of expensive new interventions, it was indeed refreshing to read the results of a well-conducted study using an intervention available to all. Data generated more than two decades ago established the benefit of non-steroidal anti-inflammatory drugs like aspirin for the prevention of colorectal cancer. It is gratifying that this simple intervention has additional scientific support both for those with high-risk predisposition, as well as other patients at risk for this relatively common, yet potentially lethal, malignancy.