The best answer to this question, I tell both my patients and loved ones, is: it depends on you.
As the U.S. Preventive Services Task Force affirmed this week in its updated draft recommendations on breast cancer screening, "The decision to start screening mammography in women prior to age 50 years should be an individual one. Women who place a higher value on the potential benefit than the potential harms may choose to begin biennial screening between the ages of 40 and 49 years." The Task Force went on to suggest that women with first-degree relatives who had breast cancer might be more motivated to start screening in their 40s.
What this decision shouldn't depend on is being bullied by one's doctor into getting a mammogram "just to be safe." Screening mammography's benefits and harms are closely balanced, and as two of my mentors in preventive medicine observed, some women might reasonably decide to say no:
Over the years we have learned more about the limited benefits of screening mammography, and also more about the potential harms, including anxiety over false-positive results and overdiagnosis and overtreatment of disease that would not have caused health problems. More and more, the goal for breast cancer screening is not to maximize the number of women who have mammography, but to help women make informed decisions about screening, even if that means that some women decide not to be screened.
Two women at "average risk" for breast cancer might make different decisions after they turn 40, depending on how concerned they are about dying from cancer, being diagnosed with cancer, and their tolerance for harms of screening. One well-informed female science journalist might choose to start being screened. Another female reporter, equally well-informed, might choose to opt out. Neither of these decisions is right or wrong on an individual or population level, regardless of the apocalyptic protests of self-interested radiology groups.
What concerns me is how current quality measurement and pay-for-performance approaches could end up pressuring more doctors to behave like bullies and drive up health care costs. Fee-for-service Medicare already spends about $1 billion each year on mammography; across all payers, about 70% of U.S. women age 40 to 85 years are screened annually at a cost of just under $8 billion. Doctor A is not necessarily a better doctor who deserves higher pay than Doctor B because more of Doctor A's patients get mammograms. In fact, the opposite might easily be true.
A recent study estimated that patients and insurers in the U.S. spend an additional $4 billion annually on working up false-positive mammogram results or treating women with breast cancer overdiagnoses. That's an extraordinary amount to spend for no health benefit, and it could be substantially less if physicians had the time and resources to explain difficult concepts such as overdiagnosis. But that doesn't appear to be where we're headed.
Finally, the notion that has been written into law in nearly half of the states in the U.S. requiring that women with dense breast tissue be notified so that they can get supplemental testing for mammography-invisible cancers is particularly misguided. The USPSTF's review found no proof that breast ultrasound, MRI, or anything else improves screening outcomes in women with dense breasts, and a sizable percentage of women can transition between breast density categories over time.
