New Mammogram Recommendations Betray Women, Doctors and Science
This week the US Preventive Services Task Force (USPSTF) revised their recommendations for screening mammograms. Their recommendations have ignited much controversy and have weakened the credibility of a formerly objective scientific body.
This post is longer than usual. It deals with an important subject in some detail. For the readers who like to delve into the details and see the data, set this aside for when you can give it some time, follow the links, and check out the articles yourself. If you just want an executive summary, skim for the bold face type and read the conclusion.
What did the USPSTF recommend?
My regular readers know that the USPSTF is a national body of scientists who periodically assess the medical literature and provide recommendations about preventive tests and treatments. Because they are unaffiliated with any specific interest group, the USPSTF developed a reputation as the most objective and unbiased source of medical recommendations. For every test or therapy they reviewed, they weighed patient benefit against the potential for patient harm (regardless of cost) and reported whether the intervention was beneficial, harmful or that there is insufficient evidence to decide. I personally looked to their recommendations and wrote about them frequently.
The USPSTF’s last review of the literature regarding mammograms was in 2002. At that time they recommended a mammogram every one to two years for women aged 40 and older.
This week, in the Annals of Internal Medicine they published their new recommendations, supported by two articles detailing the scientific evidence that was reviewed to reach their conclusions. Their current recommendation (link 1 below) for mammograms is
The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take into account patient context, including the patient’s values regarding specific benefits and harms.
The USPSTF recommends biennial screening mammography for women between the ages of 50 and 74 years.
The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older.
So the major changes from 2002 are that
- mammograms are no longer recommended between the ages of 40 and 49,
- between 50 and 74 mammograms are recommended every two years, rather than every one to two years, and
- there is insufficient evidence about the benefits and harms of mammograms in women 75 years and older.
Shockingly, the first two points are entirely contradicted by the scientific evidence on which the recommendations are based.
What are the benefits and harms of mammograms for women in their 40s?
The article which examines the harms and benefits of mammograms in different age groups can be found at link 2, below. Table 1 (Mammography screening reduces breast cancer mortality for women aged 39 to 69 years.
So if mammograms have a life-saving benefit for women in their 40s, albeit a much smaller one than for women in their 50s or 60s, why would they not be recommended? Perhaps the harms caused by mammograms in that age group outweigh the benefits.
The article also methodically reviewed harms caused by mammograms. The risk posed by radiation exposure due to mammograms was studied without conclusive evidence of significant harm. The pain, anxiety and distress associated with undergoing mammograms and being told about potentially abnormal results were also studied. Most women surveyed reported that the pain and anxiety would not deter them from future mammograms. The most important harms that may result from mammography is a biopsy to determine if an abnormality is benign or malignant, additional imaging that may be required, and overdiagnosis, which means the diagnosis of breast cancer that is so slow-growing it is unlikely to shorten the woman’s lifespan.
(2) ” target=”_blank”>The Annals of Internal Medicine article studying how frequently mammograms should be done: Effects of Mammography Screening Under Different Screening Schedules: Model Estimates of Potential Benefits and Harm
New York Times article: ” target=”_blank”>Mammogram guidelines spark heated debate