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‘Baby aspirin may reduce risk of breast cancer,’ says Washington Post, omitting some major limitations of the study


3 Star


For women, baby aspirin may reduce risk of breast cancer

Our Review Summary

association is not the same as causationThe story focuses on a recent paper published in the journal Breast Cancer Research, which addresses breast cancer risk and regular use of aspirin in low doses. The story notes that regular use of low doses of aspirin may reduce the risk of breast cancer in women. Or it may not, we would like to add.

That’s an important qualifier, since it is impossible to know whether the aspirin affected breast cancer risk based on this study. That’s because this was an observational study — meaning that it could detect a correlation between aspirin use and breast cancer, but not whether the use of aspirin was actually responsible for lower rates of breast cancer. That’s a key distinction, and we wish the story had explained it explicitly. That said, this story addresses the issue more successfully than a related news release, which we reviewed earlier. The story also does a better job of addressing potential harms.


Why This Matters

As we noted in our review of the related news release, breast cancer is the second most common type of cancer-related death among women in the United States and is diagnosed in hundreds of thousands of women each year. That means many thousands — if not millions — of women and their loved ones are on the lookout for things they can do to reduce their risk of developing breast cancer. If ever there is a time to delve into details, such as how other steps women can take to reduce their risk, or how this fits into the existing body of work on aspirin and reducing cancer risk, this would seem to be it. But news stories should take pains to spell out limitations of research and not overstate what a study found.


Does the story adequately discuss the costs of the intervention?

Not Applicable

Cost isn’t mentioned. This may be because the story assumes the public knows that low-dose aspirin is inexpensive (a year’s supply would likely be less than $20). It’s good to make that clear, but because of the minimal cost will rate it N/A.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The story makes the same mistake here that the news release did, sharing only relative risk reduction numbers — not the actual numbers of people who reduced their risk of breast cancer by taking aspirin. In addition, the story would have been stronger if it had explained that observational studies, like this one, cannot determine whether a specific intervention (i.e., aspirin use) was responsible for reducing cancer risk.

Does the story adequately explain/quantify the harms of the intervention?


The story notes that aspirin can increase risk for internal bleeding, and says that women should consult a doctor before beginning a daily-aspirin regimen. This is satisfactory–but barely–since the magnitude of this potential harm is not mentioned.

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

As noted above and in our review of the news release, observational studies like this one can only identify correlations. These studies can’t prove a causal relationship — i.e., that the action (taking aspirin) caused the result (reduced risk of breast cancer). The story does not address that head on. The story also doesn’t address whether other factors — such as age or weight — may have contributed to the difference in breast cancer rates. The story does, however, address hormone therapy and alcohol use among study participants, and explains why those factors are important. That’s a plus. Lastly, the story notes that most of the study participants were white, but doesn’t explain to readers why that is relevant.

Another omission in the story is that more than 4,100 women who had developed breast cancer before the 10-year follow-up were excluded from the study. This should have been mentioned as a limitation. We wonder how these women who were excluded differed in their low-dose aspirin intake from those who developed breast cancer later on.

Does the story commit disease-mongering?


No disease mongering here.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

The story doesn’t note who funded the research, nor does it incorporate input from independent sources.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

There are a host of things that women can do to reduce their risk of breast cancer, though all of it’s based on observational data, and aren’t powered to prove that reducing the behavior actually reduces breast cancer. There should have been at least some discussion about these factors.

Does the story establish the availability of the treatment/test/product/procedure?

Not Applicable

Low-dose aspirin is already widely available and is used by many women to reduce their risk of cardiovascular disease.

Does the story establish the true novelty of the approach?

Not Satisfactory

It’s not clear from the story what is novel about this study. A reader who searches online for related material may run across this news release from the American Cancer Society on aspirin use and colorectal cancer. Is this different because of the type of cancer? Because of the dose of aspirin? Both? It’s always good to help readers place new findings in context, and often dicey to assume that readers will automatically understand how the new findings fit into the broader research on the topic.

As the news release explained: “This study differed from other studies that have looked at aspirin and cancer risk because it focused on the dose levels of the aspirin women had taken and tracked the frequency of the use of low-dose aspirin as opposed to regular aspirin.”

Does the story appear to rely solely or largely on a news release?


The story contained information about the harms of aspirin, which was not in the news release, which we reviewed. This is a barely passing satisfactory since the story mostly otherwise uses information from the release, but at least not verbatim.

Total Score: 3 of 8 Satisfactory


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