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Is Mammographic Screening Effective?

Dr. Bruce CampbellDr. Bruce Campbell is the Chief Medical Officer of BAN Agency, C.M. Smith, where he brings over 25 years of executive experience in healthcare, information technology, and managed care to their clients. He has held executive staff and operating positions in healthcare services companies, managed care plans, integrated delivery systems, medical groups, and healthcare information technology companies. His background includes having served as a Senior Vice President of Operations and the Chief Medical Officer of a national managed care company, and tenure as the Chairperson of the Audit Committee of the Board of Directors of a public company operating Medicare Special Needs Plans and disease management programs.


Earlier this week a study was published in the British Medical Journal (highly respected peer-reviewed publication) questioning the effectiveness of screening mammography in reducing breast cancer mortality in women between 40 and 59 years of age.

Screening Mammography Study Details

The study commenced in 1980 and:

  1. It randomized women to either a yearly mammography or no mammography arm for a 5 year period (1980 – 1985);
  2. After 1985, the women accessed care as they wished; and,
  3. Women were followed for a total of 25 years and mortality from breast cancer was recorded.

The authors conclude that:  "Annual mammography in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care when adjuvant therapy for breast cancer is freely available. Overall, 22% (106/484) of screen detected invasive breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial." In their discussion, they question the appropriateness of screening mammography in women in this age range.  The article and its controversial conclusions have been picked up by national media (an article regarding the study was featured prominently in the New York Times), news wires and television networks.  Undoubtedly, clients, employees and even family members have heard about it as well.

In my role as Chief, Health and Informatics Services for the smart partners of Benefit Advisors Network, I’d suggest that employee benefits consultants responsible for planning and implementing wellness programs and monitoring gaps in care for screening mammography should be aware of some background information and criticisms of the study.

Problems with how the Mammogram Study was Conducted

A response (from a professor of radiology at Harvard who reviewed the trial in the 1990's) written to the editor of the BMJ within a day or two of publication of the article is the best synopsis of the substantial criticism of the study that has been voiced by a number of prominent physicians and medical organizations.

  1. Even if the study methodology was perfect, important screening guidelines are NEVER changed on the basis of a single study; confirmatory evidence from a separate source(s) conducting their own trials is required;
  2. In the case of this study, there are very significant problems with how the study was conducted;

a. Substandard equipment (second hand and dated) was used for the mammograms (that were conducted in the 1980's);

b. There was no training for the technicians taking the mammograms; and,

c. No training in reading mammograms for the radiologists who interpreted them.

The detection rate of cancers in the study was well below what would've been expected at the time and is probably the result of the factors above.

Is Mammography Study from British Medical Journal Credible?

In short, it appears that substandard mammography was no more effective than a clinical exam at detecting breast cancer (no surprise), and that the mammography group was unfairly burdened with a significant number of breast cancer patients. The patients in the trial were to have been randomized between a mammography and no mammography arm.  There is compelling evidence to suggest that this did not happen, and that individuals with suspected or clinical breast cancer were assigned, in biased fashion, to the mammography arm of the trial so that they would receive immediate treatment. Although the above might sound like nit-picking, these are concerns that are serious enough, in the opinion of a number of experts in the field, that the study should be considered invalid. If the assertions are correct, I would agree with the criticisms and conclusions.

Bottom Line to Employers: Although the results of the study have been widely publicized, there appear to have been very serious problems with how the study was conducted.  These are serious enough to call into question the validity of the results and the study's conclusion.  In addition there are many other studies showing the effectiveness of screening mammography in women over the age of 50.  So what does it mean to employers who sponsor group health plans and wellness programs?  Given these concerns, we recommend that plan sponsors continue to implement programs that encourage women in appropriate age groups to undergo regular screening mammography.

There is disagreement among various groups regarding the details of screening, but all groups recommend for it.  A reasonable consensus is for biennial screening of women between 40 and 50, and annual screening for women over 50.  Current screening guidelines are presented in the table below:  

Mammographic Screening

If you have questions about whether or not this study and the experts' interpretations of the study's validity, could impact your employee benefits and group health insurance decisions, contact your Benefit Advisors Network smart partner by viewing our member directory or use our contact us page and we'll put you in touch with a local benefit advisor to help answer your concerns.

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