Is the mammography debate an example of 'fake science'?

2016 09 06 13 31 23 491 Question Mark Blue 400

In today's world of "fake news" and "alternative facts," is the debate over mammography screening one of "fake science"? It might be, according to a paper published recently in BMC Medical Ethics from a Norwegian researcher who claims to show how breast screening researchers fit facts to suit their beliefs.

The debate over breast screening is one of the most polarized in medicine, with proponents and skeptics of screening serving up contradictory studies, according to Bjørn Hofmann, PhD, from the Norwegian University of Science and Technology in Gjøvik. What's most confounding about the debate is that researchers from opposing sides often come to radically different conclusions from the same data (BMC Med Ethics, January 27, 2018).

Hofmann sees mammography as an example of a polarized scientific discipline, in which "reputable scientists hold radically opposed views leading to the segregation of the scientific community into groups in part constituted by their opposition to other groups in the field." Researchers in such polarized fields often self-identify as proponents of positions that must be defended, leading them to discount arguments and data that would normally be seen as a natural part of scientific debate.

In an effort to prove his point, Hofmann analyzed eight research studies on breast screening, specifically looking into whether there was a relationship between each study's findings and the leanings of the study's lead researcher. Because much of the debate in mammography focuses on the benefits and harms of screening, he focused on what he felt were the two main points of disagreement between the camps: the mortality benefit of screening and the rate of overdiagnosis, or detection of lesions that would never pose a risk to individuals during their lifetime.

To rate the studies, Hofmann used a metric called overdiagnosis to mortality reduction ratio (OMRR): the ratio of overdiagnosis over the rate of mortality reduction. The higher the ratio, the more negative the study was regarding the benefits of mammography.

Next, Hofmann had two experts in polarized conflict-of-interest studies grade the authors of the eight publications on their attitude for or against mammography screening. The experts used a five-point scale, with a 5 indicating that the researcher was strongly in favor of breast screening and a 1 indicating that he or she was strongly against it.

Hofmann found that the OMRR values correlated closely with the attitude grades; that is, promammography researchers produced studies that gave breast screening high marks, while antimammography researchers produced the opposite.

Mammography study findings and author attitudes toward screening
Study Lead researcher Overdiagnosis to mortality reduction ratio (OMRR) Attitude toward screening
U.K. Breast Screening Programme Dr. Prue Allgood 0.4 4
Euroscreen study Dr. Eugenio Paci 0.5 5
Swedish Two-County Trial Dr. László Tabár 0.5 4
Florentine screening program Dr. Eugenio Paci 0.6 5
Norwegian Breast Cancer Screening Program Dr. Solveig Hofvind 1.7 5
U.S. Preventive Services Task Force Dr. Albert Liu 2.71 4
Marmot report Dr. Sir Michael Marmot 3 4
Norwegian Research Council Dr. Roar Johnsen 5 2
Cochrane Collaboration Dr. Peter Gøtzsche 10 1
Lower OMRR numbers are favorable toward mammography, while lower "attitude" numbers are unfavorable.

The findings reflect the polarization present in research on mammography screening, according to Hofmann. Similar trends are occurring in other fields, which could threaten public perceptions of the objectivity of science.

"Published research on mammography screening for breast cancer illustrates the problem of science being directed by strong professional interests, where some researchers continuously publish positive results while others publish negative results on the same issue -- even when based on the same data," he wrote.

Polarization in scientific research should be acknowledged as such, Hofmann concluded. He recommended that editors require researchers to state their "polarized conflict of interest" when submitting manuscripts for publication. He also recommended that editors require article reviewers to assess polarization and employ outside experts when reviewers or editors are too polarized themselves to make assessments.

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