The Associated Press reported Friday on the conflicting mammogram guidelines that have emerged from several U.S. health organizations. The newest recommendation, from the American College of Physicians, advises women at average risk to start screening at 50 and get mammograms every other year through age 74 — a break from the growing movement toward beginning in the 40s.
That guidance, released last month, surprised clinicians because most other major groups have moved earlier. The U.S. Preventive Services Task Force, an influential federal panel, now calls for every-other-year mammograms starting at 40, while the American Cancer Society recommends yearly mammograms from 45, with a choice to begin at 40. The cancer society also says women who are healthy should not stop screening at any particular age, whereas the physicians’ group suggests doctors can ask women 75 and older if they wish to discontinue routine checks.
The disagreement stems from genuine uncertainty about how to weigh the benefits and harms of screening for women without known risk factors. “Breast cancer is not one disease,” said Dr. Laura Esserman of the University of California, San Francisco, who is leading research to better stratify women’s risk. “So how in the world does it make sense to screen everybody the same when everyone doesn’t have the same risk?”
Mammograms reduce breast cancer deaths by catching tumors before they spread, but they also lead to follow-up tests, stress, and sometimes treatment of slow-growing cancers that might never have caused harm. The trade-off is narrower for women in their 40s, said Dr. Carolyn Crandall of UCLA, who chaired the American College of Physicians review: “We’re not saying there’s no benefit” from mammograms in that decade, but “there’s a narrower balance between the benefits you could get and the harms in 40- to 49-year-olds.” The American Cancer Society countered that breast cancer incidence in 45- to 49-year-olds is closer to that of 50- to 54-year-olds, which supports beginning annual screening at 45, said Robert Smith, the society’s expert on early cancer detection.
Nearly half of women over 40 have dense breast tissue, a factor that makes it harder for standard mammography to find tumors and slightly elevates cancer risk. Many experts say it is not yet clear whether women with dense breasts should add ultrasounds or MRIs, but the new college guidance advises considering 3-D mammography, known as digital breast tomosynthesis or DBT, which can improve cancer detection in dense tissue.
Looking ahead, a trial called WISDOM — involving nearly 46,000 women — used age, genetic testing, lifestyle, health history and breast density to classify participants as low, average, elevated or high risk, then assigned screening schedules accordingly. The risk-based approach matched the cancer-detection rate of annual screening, Esserman’s team reported in the journal JAMA. One surprising finding: about 30% of women whose gene tests showed an increased risk did not report a family history of breast cancer. Esserman hopes the results will begin to influence guidelines, and other researchers are working on AI tools that could assess a woman’s short-term breast cancer risk by analyzing her mammogram images.
In the meantime, women are advised to talk with their doctors about close relatives who have had cancer, their overall health, and other risk factors such as whether they have had children and at what age. “Breast screening works best when it’s done regularly,” Smith said, regardless of which starting age and interval a woman chooses.