April 2, 2014 — Women and their physicians should discuss whether and when they would benefit from routine mammograms, according to two new reports that call for more individualized decision-making on the screenings, USA Today reports (Painter, USA Today, 4/1).
The findings, published Tuesday in the Journal of the American Medical Association, add to other recent research suggesting that mammograms prevent relatively few deaths and can sometimes lead to unneeded treatment of cancers that would have never caused problems.
Similar research led the U.S. Preventive Services Task Force to revise its recommendations on when women should begin mammograms, while the American Cancer Society has not changed its guidelines (Beck, Wall Street Journal, 4/1). ACS recommends that women have yearly mammograms beginning at age 40 and continue to do so "as long as a woman is in good health," while USPSTF advises that women wait until age 50 to begin the screenings and only receive them every other year (USA Today, 4/1).
For one new study, Harvard University researchers reviewed all mammogram research since 1960, as well as evidence on the harms of false-positive test results and over-diagnoses.
The researchers concluded that while mammograms have notable benefits, their advantages have been oversold, while the potential harms have been understated. According to the study, while annual mammograms reduce the risk of death from breast cancer by almost 19%, the benefit varies widely based on a woman's underlying cancer risk and age. For example, about 1,904 women in their 40s would have to have a mammogram to prevent one death, compared with 377 women in their 60s.
The reason for the variation is that the chances of developing breast cancer increase as a woman ages. For instance, a 40-year-old woman has a 1.5% risk of developing breast cancer over the next decade, which increases to 2.3% risk at age 50 and 3.5% risk at age 60.
In addition, the study found that nearly 19% of women who received a breast cancer diagnosis from a mammogram were over-diagnosed, meaning they received unnecessary chemotherapy, surgery or radiation for cancers that would not have caused death.
The researchers wrote, "Decisions about mammography should involve discussion of risks, benefits, uncertainties, alternatives and patient preferences" (Schute, "Shots," NPR, 4/1). Study lead author Nancy Keating of Harvard Medical School added, "There isn't a one-size-fits-all on mammograms" (Wall Street Journal, 4/1).
Study on Older Women
Meanwhile, a second study, focusing on older women, found that starting at age 75, women should reconsider whether they should continue routine mammograms.
According to the study, there have not been any randomized, controlled trials focusing on mammography in women ages 75 and older, so there is no way of knowing how effective the screenings are at extending those women's lives.
Overall, the study suggested that the harms of mammogram screenings likely outweigh the benefits in women who will probably live less than 10 years. The study's authors recommended that women who think they will live longer than a decade should discuss the benefits and risks of mammograms with their physicians ("Shots," NPR, 4/1).
ACS Chief Cancer Control Officer Richard Wender said, "There is a point at which screening for cancer should stop," adding that some women with health problems that are more likely to end their lives before breast cancer could be getting unnecessary mammograms.
However, Wender noted that the new studies included decades-old research that might have underestimated mammograms' benefits and not included current breast cancer treatments. He added that although mammograms do have drawbacks, he "continue[s] to believe that most people in the United State place a high value on preventing a cancer death and will put up with a lot of downsides" (USA Today, 4/1).
Keating said, "The more we screen for cancer, the more we find it. But we could have saved some of these women the angst of being told they have cancer." She added, "The challenge is, we can't tell which are the aggressive cancers" (Wall Street Journal, 4/1).