New Mammography Study: How Numbers Can Be Wrong

New Mammography Study: How Numbers Can Be Wrong

We love science. Science is the way we move forward in the fight against breast cancer. One of the things we learn as physicians is to critically analyze results that are reported in journals as science is only advanced when scientific procedures and protocols are rigorously followed.


The New York Times recently reported on a  study published  in the British Medical Journal (BMJ) based on information from the Canadian National Breast Screen Study (CNBSS). Unfortunately, this study has several design flaws, making its conclusions suspect.


This research has received a burst of coverage not only in the medical community but also in our national media. We are happy for the coverage as it keeps breast health fresh in women’s minds. However, we have major reservations about the conclusions which are being touted from the study.


Upon review of this study from the BMJ we stand with the Society of Breast Imaging and the American College of Radiology on this subject. The BMJ report is a further review of women who participated in a Canadian study in 1980-1988, reviewing mortality information on those women up to 2005. This includes no new information other than review of mortality or death data on the women in the original study for a longer time period. The mammography and clinical screening portion of the study lasted for a total of 4-5 years only.


The original study has been widely criticized on several grounds, all of which we will not discuss here. However, a thoroughly concise critique of the study can be found here. One of our biggest problems with the study is that mammography performed in the years in the study is not the mammography performed today. The quality of mammography included in the study was also suspect, as even the reference physicist for the study found issues with the quality of mammography, calling it below state of the art, even for the time. To base current practice recommendations on a study which used mammography of questionable quality is wrong.


Multiple other research studies have shown annual screening mammography  starting at age 40 (potentially earlier if in a high-risk category) saves lives.


Mammography is not perfect – we who work with it daily recognize its limitations and yearn for a more accurate, easier tool. However, for today, mammography is a proven screening tool that is fast, readily available, relatively inexpensive and well-tolerated by women. Early detection of breast cancer saves lives. We cannot change current medical practice based on flawed research.




Originally published 2/13/14 on