Regular Mammograms in Women 70 and Older Lead to Overdiagnosis Risk, Study Finds

Screening recommendations for breast cancer often don’t include women aged 75 and older due to limited evidence of its benefits. For example, the United States Preventive Services Task Force only recommends regular mammograms through age 74. A new study looked more closely at screening in older women and found that there may be some risks.

Researchers from the Yale School of Medicine recently looked into the rates of overdiagnosis in women aged 70 and older who were still getting regular mammograms. According to findings published in Annals of Internal Medicine, more than 30% of breast cancers diagnosed in screened women aged 70 to 74 were estimated to be overdiagnosed, meaning the tumors detected during screening would not likely have caused any symptoms or harm. This percentage increased as women aged, which the researchers say illustrates possible harms of continuing screening into old age.

Senior woman at doctor's office

Ilana Richman, first author and assistant professor of medicine at Yale School of Medicine, explains, “Overdiagnosis can occur when cancers grow very slowly or if a person’s life expectancy is short. Finding these breast cancers can lead to worry and can result in intensive treatments, without improving length or quality of life. The findings from this study emphasize the need for a careful evaluation of the benefits and harms of screening older women.”

The research, funded by the National Cancer Institute (NCI), involved NCI data from more than 54,000 women aged 70 and older with no history of breast cancer and who had a recent screening. Among those between the ages of 70 and 74, roughly 6% of women who were regularly screened had been diagnosed with breast cancer, compared with 4% of women who had not undergone screening. The researchers say this indicates that many of the cancers detected did not cause symptoms or show up among unscreened women.

It was also estimated that 31% of the cancers detected during screening in women aged 70 to 74 were unlikely to be symptomatic or cause any harm. This figure went up to 47% in the 75 to 84 age group and 54% in those aged 85 and older. At the same time, the researchers say screening was not associated with a substantially lower risk of breast cancer death.

Senior woman seated with nurse

While their findings point to the potential harm of overdiagnosis, the researchers acknowledge that screening decisions are up to the individual and their doctor.

Richman says, “While our study focused on overdiagnosis, it is important to acknowledge that overdiagnosis is just one of many considerations when deciding whether to continue screening. A patient’s preferences and values, personal risk factors, and the overall balance of risks and benefits from screening are also important to take into account when making screening decisions.”

The researchers also write that the question of whether the benefits of screening in older women balance out the possible harms must still be answered.

When it comes to screening in younger women, a 2021 paper written by Australian doctors argued that benefits of regular mammograms outweigh the risks of overdiagnosis. You can read more about that here.

Doctor showing imaging to senior patient
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