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Benefit of mammograms even greater than thought

Rating

2 Star

Benefit of mammograms even greater than thought

Our Review Summary

This story reports on the results of a long-term Swedish study showing that 29 years after their first mammogram, women who were invited to get routine screening had a significant reduction in breast cancer mortality compared to those who received usual care. This story failed to meet many of our criteria. For instance, the story does not give readers a balanced review of the benefits and harms, provides no cost information, lacks independent perspective, fails to report absolute data, and it does not include a discussion of the study limitations.

 

Why This Matters

The available evidence on the utility of screening mammograms is conflicting and complex and this story muddies the waters even more by largely ignoring the discussion of harms associated with mammography and introducing a suggested screening schedule, which this study was not even designed to address. In addition, the story line about the mammography debate is not, “Does screening save lives or not?” Rather, it is, “Is it worth it for an individual woman to be screened, when for some (e.g. 40-50 year olds), the benefit is quite small?” The U.S. Preventive Services Task Force did not say that screening did not reduce mortality. It said that for some women, the trade-off between that benefit and the potential harms is a close call and should be weighed by the woman and her physician.

CNN, by comparison, included a response from the chair of the USPSTF – something this story omitted.

The LA Times blog headline was “Mammograms can find breast cancer, true, but cost-benefit question remains” – more skeptical framing that this story didn’t approach.

Criteria

Does the story adequately discuss the costs of the intervention?

Not Satisfactory

This story did not mention the cost or insurance coverage for mammograms, though it did allude to the expense of having additional biopsies and tests to distinguish between a cancerous and noncancerous lesion found via screening. 

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

Not Satisfactory

The story reports the percentage difference in death rates, without including absolute numbers, but it does quote the lead study author in presenting the Number Needed to Treat (NNT) to explain the results. In this case, he estimates that 1,000 women will need to be screened for 10 years to prevent 3 deaths from breast cancer.

The story evokes the U.S. Preventive Task Force and the controversy associated with the revised recommendations for women aged 40-49 years, but the study does not break down the results by age, so one cannot be confident that these results will influence the current recommendations in any way. Other stories addressed this issue; this one did not. Furthermore, the lead author suggests that screening should take place every 18 months for women age 40-54 and every 2 years for women 55 and over, but results from this study do not address the issue of screening frequency.

The story also misstated the recommendations of the U.S. Preventive Services Task Force by saying that they “recommend against routine screening” for women in their 40’s. Their recommendation was that “the decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient’s values regarding specific benefits and harms.” The story perpetuates the notion that the mammography debate is about who is right (those who advocate mammography) and who is wrong (those who do not) regarding whether mammography “saves lives.”

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

Not Satisfactory

This story briefly discussed a few of the harms associated with mammograms, specifically the stress and anxiety caused by false positive results; however, it should have also mentioned the harms associated with unnecessary treatment of cancers that may not cause problems or be life-threatening. Also, focusing on this issue of the “stress” for women who receive a false positive result puts too much emphasis on these psychological harms. Counterposing “stress” to “lives saved”, though valid, is not persuasive.

 

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

Not Satisfactory

There is a lot of controversy surrounding this Swedish dataset and the story should have acknowledged these methodological concerns. Our blog post from October 4, 2011 outlines these potential limitations.

Does the story commit disease-mongering?

Satisfactory

The story did not exaggerate the prevalence or seriousness of breast cancer.

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

Not Satisfactory

This story included a quote from a radiologist not involved in the study, but one could argue that a radiologist has a vested interest in mammography screening. (And why/how was that radiologist chosen?) Additional perspectives would have been welcomed. For instance, why was no one from the U.S. Preventive Services Task Force asked to comment? That is difficult to understand.  And while the study authors had no potential conflicts of interests to disclose, it’s well known that some of the study authors are long-time proponents of mammography screening and this is worth mentioning.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

This story only briefly touches on the fact that “everyone must make up their own mind” regarding mammography, but it’s not explicit about the fact that women may choose not to have routine mammograms. In addition, the story indicates that the U.S. Preventive Services Task Force made their recommendations against routine screening in women 40-49 to avoid unnecessary biopsies and anxiety, but it should be mentioned that these recommendations were also implemented to minimize needless treatment, including surgery, chemotherapy and radiation therapy.

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

Not Applicable

The availability of mammograms is not in question.  

Does the story establish the true novelty of the approach?

Satisfactory

It’s clear from the story that this is the longest-running breast cancer screening study and it’s the first study to show that absolute benefit of mammography screening increases over the long-term. However, it would have been helpful to point out that the first results were reported in 1985 and there were a number of subsequent updates, as well.

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

Satisfactory

This piece does not rely on a press release.

Total Score: 3 of 9 Satisfactory

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