Women who continued breast cancer screenings when they reached age 70 had no lower chance of dying from the disease, and just getting a mammogram could instead set them on a path toward unnecessary risks, according to a new study from Yale University.
The findings, published in Annals of Internal Medicine, suggest that , meaning that the cancer found during the screening would not have caused symptoms in a person’s lifetime. (For context, the average life expectancy of a woman in the U.S. is 79 years, according to the Centers for Disease Control and Prevention.)
Overdiagnosis can be harmful because it carries the risks of complications from overtreatment, plus financial and emotional hardships and unnecessary use of limited resources.
For the study, researchers analyzed data for 54,635 women aged 70 and older and compared the rate of breast cancer diagnosis and death among women who did and did not have mammograms during a 15-year follow-up period.
The rate of breast cancer in the study among women aged 70-74 was 6% for women who were screened and 4% for women who were not screened. The researchers estimated that 31% of the cases were potentially overdiagnosed. Among women aged 75-84, breast cancer was found in 5% of women who were screened, compared to less than 3% of unscreened women. Their estimated overdiagnosis rate was 47%. Finally, 3% of women aged 85 and older who were screened had breast cancer detected, compared with 1% of women in the unscreened group. For the older group, the overdiagnosis rate was 54%.
“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,” researcher and Yale assistant professor of medicine Ilana Richman, MD, said in a statement. “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.”
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