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

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 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 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 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.”