imagesLast year, Miller et. al. have published one of the largest and longest randomized controlled trials (RCTs) in North America, Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial (2014), putting doubts on the effectiveness and benefits of breast cancer screening.

Immediately the study got a lot of media attention (e.g.: The Globe and Mail and National Post).

Shortly after, Dr. D. Gorski has written a timely, detailed blog post dissecting the study and exploring the possible methodologic flaws and biases.

An article published in May 2015 by Heywang-Köbrunner et. al., Conclusions for mammography screening after 25-year follow-up of the Canadian National Breast Cancer Screening Study (CNBSS), have summarized the large body of research papers criticizing the methodological issues concerning design, quality assurance, and evaluation of Miller et. al.'s study (2014). Quoted from Heywang-Köbrunner's study (2015):

Sixty-eight percent of all included cancers were palpable, a situation that does not allow testing the value of early detection. Randomisation was performed at the sites after palpation, while blinding was not guaranteed. In the first round, this "randomisation" assigned 19/24 late stage cancers to the mammography group and only five to the control group, supporting the suspicion of severe errors in the randomisation process. The responsible physicist rated mammography quality as "far below state of the art of that time". Radiological advisors resigned during the study due to unacceptable image quality, training, and medical quality assurance. Each described problem may strongly influence the results between study and control groups.


Picture Courtesy:

Breast cancer awareness - http://bicrad.com/blog/dr-james-brenner-talks-breast-cancer-screening-and-usphstf/

 

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