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Mammograms Cut Breast Cancer Death Rates, But Only Modestly: Study


3 Star

Mammograms Cut Breast Cancer Death Rates, But Only Modestly: Study

Our Review Summary

This story does a fairly good job carefully walking readers through a new study on a highly charged topic: the benefits of mammography. It pulls together a range of voices from different perspectives but allows one voice, that of the pro-mammography radiology community, to dominate the others. Given how thorough the story is in reviewing the science behind the new findings, it should also have talked about the costs associated with mammography, the harms associated with unnecessary procedures, and the variety of screening protocols and treatments available – including foregoing screening.


Why This Matters

We are in a bit of a mammography moment right now. Clinicians and policymakers are talking about the risks, benefits and costs, and, literally, lives could be saved or lost based on the outcome of these discussions. More than ever, patients need clear information to help them decide how to make decisions about their own health that may end up being in conflict with their doctor’s advice, depending on where their doctor stands in this debate. Stories like can help bring clarity to the discussion by taking pains to stick to the science and avoid "muddying the waters" with emotion or financial considerations.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

This is a big one to miss. Mammograms usually are covered by insurance, but because of the conflicting guidelines, there is a concern that some insurance companies won’t want to cover mammograms for women under 50. Also, if a woman doesn’t have insurance and falls into the right demographic, they will need to foot the bill. It would not have been difficult to find out how much they cost and even to find someone to estimate how much is spent every year in the U.S. on mammograms.

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

Not Satisfactory

Right off the bat, the story says, "Routine mammograms account for only about one-third of the decline in breast cancer death rates, according to a large new analysis of data from Norway’s expansive breast cancer screening program." It takes too long, we think, for the story to follow this up with more data. Instead, we are given this dubious statistic from an oft-quoted member of the American College of Radiology. He says that "since the advent of routine mammograms in the 1990s, the rate of death from breast cancer has dropped 30 percent." Ask an oncologist about what has happened to cancer care since the 1990s, and you may get a different answer as to why that death rate has dropped.

The story goes on to say, "The difference in the rate of death from breast cancer among women in the screening group versus the control group was 28 percent. In comparison, there was an 18 percent reduction in the rate of death in the non-screened group versus the control group, the study found. In other words, breast cancer screening was associated with a reduction in death — but only accounted for 10 percentage points of the difference." But we urge stories to include the absolute number of deaths in both groups and to include the number needed to treat (or screen) to save one life.  In fact, the absolute numbers and the NNT were in the accompany editorial by Dr. Gilbert Welch.  All they had to do was cite them.

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

Not Satisfactory

In the fourth graph, we are given this great quote from the lead author, Dr. Mette Kalager, an epidemiologist with the Cancer Registry of Norway in Oslo and a visiting scientist at the Harvard School of Public Health in Boston. "Women should be informed that the benefit is smaller than expected, and there should be a balanced discussion on the benefit and the possible harms of screening, such as overdiagnosis, false-negative and -positive tests and psychological distress." Given how thorough the story was in other areas, we hoped to see some of these potential harms actually broken down later in the story. What has research shown to be the estimated amount of overdiagnosis, false-negatives and false-positives? Some of these numbers would have been a nice counterpoint to some of the statements elsewhere in the story touting the benefits of mammograms. 

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

The story clearly describes both the wide scope of the study and some of the limitations the study had. It says, for example, "Norway’s breast cancer screening program began in 1996 and was expanded two years later, with staggered enrollment by county over a period of nine years. Since 2005, all Norwegian women aged 50 to 69 have been invited to have a screening mammogram every two years, the authors said." The study ended up taking in "more than 40,000 Norwegian women [who] were followed for an average of 2.2 years." This last point is one of the reasons other researchers think the study didn’t go far enough. Had they followed these women for a longer period, the theory goes, they would have found more deaths in the women who were not screened. 

Does the story commit disease-mongering?


There is no disease mongering in this story.

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

Not Satisfactory
Normally, we would be thrilled to see this many sources in a story this short, and we are inclined to give this category a satisfactory rating largely because of the multiplicity of voices. That said, the story relies too heavily on comments from Dr. Daniel B. Kopans, director of breast imaging at Massachusetts General Hospital and a member of the American College of Radiology’s task force on promoting mammography. Kopans is given way too much leeway to opine about the study without presenting compelling evidence of his own. For example, "But Kopans noted that mammography is still the only test that has been proven to reduce the death rate from breast cancer and that this study should not divert attention away from that fact." OK. Well, by how much did it reduce the death rate? If someone who is as big of an advocate as Kopans is allowed to go unchallenged, it leaves readers with the impression that, as he puts it, the epidemiologists "looking at huge numbers" don’t understand how to "take care of women with breast problems." This raises a question of balance, especially when the story doesn’t challenge such comments coming from someone who makes a living screening women. Nonethless, because of the number of voices, we’ll give the story a hesitant satisfactory score on this.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

The story could have done a better job explaining that self-exams are also another common, although also controversial, means of detecting breast cancer and that gene testing has given rise to a subgroup of patients with the BRCA1 and BRCA2 gene mutations who have opted for aggressive prevention measures, such as complete breast removal. Cancer is a complicated disease, and some of this could have been captured, even in the limited space.

Even more broadly, it never explicity addressed the option of foregoing mammography in any detail – which is hard to overlook in this case.

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


The availability of mammograms is clear from the story.

Does the story establish the true novelty of the approach?


The story makes it clear that, far from novel, mammography is a frequently used screening procedure that is coming under new scrutiny because of mounting evidence that it does not produce the benefits early research showed.

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


The story did not rely on a news release.

Total Score: 5 of 10 Satisfactory


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