Less than 20 percent of women in the U.S. are aware that routine mammograms can lead to overdiagnosis and overtreatment of breast cancer, according to a University of Minnesota study published this month. 

The routine screenings detect cancers, including those that aren’t harmful. This may negatively impact women who are unnecessarily treated with surgery, chemotherapy or radiation. Some researchers say better health communication may be key to raising awareness of these problems.

The study was done in response to increasing numbers of professional organizations — like the American Cancer Society and the U.S. Preventive Services Task Force — recommending that women, especially those in their 40s, weigh the risks and benefits when deciding whether to get breast cancer screenings, said Rebekah Nagler, assistant professor and lead author of the study. 

“Our question is, do women in fact have the information they need to make that sort of calculation?” Nagler said.

The study also shows women aren’t aware of recent changes made to the recommended age for mammograms. 

In 2009, the U.S. Preventive Services Task Force upped the recommended age for women to receive mammograms from age 40 to 50. The American Cancer Society issued a similar recommendation, raising the recommended age to 45 in 2015. 

“These new recommendations were coming out of an evaluation of evidence that suggests that there are harms of getting breast cancer screenings when it’s not necessary,” said Sarah Gollust, associate professor and senior author of the study.

The changes also come in response to increasing knowledge about slow-growing cancers that can be benign, Gollust said. Treating these cancers can put patients through unnecessary sickness and distress, she said.

“It could be that we’re not doing a good enough job providing information about what those risks really are and how they translate and how they perhaps could affect one’s decision-making,” Nagler said.

Promoting balance between harm and benefit in cancer prevention and treatment is difficult for not only researchers but also communicators, which may contribute to low levels of awareness, said Kari Mentzer, a research assistant at the University’s School of Public Health.

“More training for everyone would be helpful,” Mentzer said. “If reporters had more science training and researchers had more media training [in] how to tell these stories to be effective so that the public hears them.”