About 38% of women in their 40s who are presented with information about the pros and cons of mammography prefer to wait to get breast cancer screening, according to results of a national survey published by social psychologist Laura Scherer, PhD, a University of Colorado Cancer Center member on the CU Department of Medicine faculty.

Scherer is also an investigator with the CU Adult & Child Center for Outcomes Research & Delivery Science (ACCORDS) and co-director of its Colorado Program for Patient Centered Decisions.

“There is a bit of an assumption out there that all women want to start screening at age 40,” says Scherer. “But when you give people the leeway to make a choice, and you inform them of the benefits and drawbacks of screening, some people, though not all, do want to wait until they are 50.”

She adds: “The people who wanted to wait until 50 were at lower cancer risk on average and were more concerned about the possible harms. Importantly, informing women did not increase the small number who never want to have mammograms.”

Scherer’s research focuses on medical decision making. Her new study, funded by the National Cancer Institute, was published recently in the Annals of Internal Medicine.

The research comes amid an ongoing conversation in the medical community about how early women should start getting mammograms, how often, and what sort of information women should get before they start screening. In recent years there has been growing emphasis on women starting screening in their 40s rather than waiting until age 50.

Informing decision making

For Scherer’s study, 495 women nationwide ages 39 to 49 without a history of breast cancer were surveyed both before and after they were presented with a package of information about screening known as a decision aid. Participants also lacked a known BRCA1 or BRCA2 gene mutation, both of which significantly increase the risk of breast and ovarian cancer.

“We wanted to investigate how women react to being informed of both the benefits and drawbacks of breast cancer screening and how that informs their decision making,” Scherer says. “Does that information matter to them, and have they heard it before?”

The decision aid the women received described both benefits and harms of screening in their 40s and included a personalized 10-year breast cancer risk estimate. Benefits cited in the decision aid included reductions in breast cancer deaths through screening, while harms included the rate of false-positive results, as well as overdiagnosis of asymptomatic cancer not likely to cause symptoms or harm in a person’s lifetime, resulting in overtreatment.

“The decision aid compared benefits and harms for screening in women’s 40s versus screening in their 50s. As you get older and your cancer risk becomes greater, your chance of receiving a benefit from screening goes up and your chance of receiving a false positive goes down,” Scherer says.

Now vs. later

Scherer reported that before viewing the decision aid, 27% of survey participants preferred to wait instead of having mammography at their current age. But after reading the decision aid, 38.5% of those surveyed said they would prefer to wait. Survey participants who preferred to wait tended to have lower breast cancer risk than those who preferred not to delay.

That doesn’t mean most women don’t ever want to be screened, Scherer emphasizes. Only 5.4% of women surveyed before receiving the decision aid said they would never want a mammogram at any age, and 4.3% gave that response after reading the decision aid.

Asked what information in the decision aid surprised them, 37.4% of the women surveyed cited information about overdiagnosis, 27.2% said information about false-positive results, and 22.9% pointed to information about screening benefits.

Scherer says the vast majority of women who said they wanted to delay screening “seemed to be making that judgment with a reasonable rationale – they were concerned about the harms, or their risk was lower.” Only a “very small minority” of participants cited false ideas about the safety of mammography, she says.

Changing guidelines

Scherer notes that the survey was conducted in 2022, before a change in breast cancer screening guidelines by the U.S. Preventive Services Task Force (USPSTF), an independent, volunteer panel of national experts in prevention and evidenced-based medicine.

At the time of the survey, the USPSTF recommended “that women in their 40s make an individual decision with their clinician on when they should start screening, taking into account their health history, preferences, and how they value the different potential benefits and harms.” Scherer says that recommendation may have had an influence on the responses some women gave in the survey.

This year, the task force shifted its guideline, saying that all women should get screened for breast cancer every other year, starting at age 40 and continuing through age 74.

In her study, Scherer writes that the USPSTF still “endorses informed choice and shared decision making [by patients and doctors] at all levels of its recommendations, but a lack of language promoting informed choice in the guideline itself may create confusion among clinicians about whether they should discuss both screening benefits and harms with patients or instead provide only information that maximizes screening uptake.”

Reducing barriers

The change in USPSTF’s guideline made it easier for some women in their 40s to have their mammograms paid for by insurance under the federal Affordable Care Act because it raised its recommendation for screening at that age past a threshold for required insurance coverage under the ACA.

“This change has expanded access to screening, and a lot of women want screening, so that’s beneficial,” Scherer says. “At the same time, people have a right to information, and they have a right to turn down preventive care if they don’t feel it makes sense for them at that time in their life. We can respect people’s autonomy at the same time as we reduce barriers to care.”

Asked what women in their 40s should take away from her research, Scherer says: “You have a right to be informed about the benefits and drawbacks of screening. And it’s important that you talk to your doctor and create a screening plan that is right for you.”

CU School of Medicine faculty who co-authored the study included Carmen Lewis, MD, MPH; Channing Tate, PhD, MPH; and Brad Morse, PhD, MA, all of the CU Department of Medicine’s Division of General Internal Medicine; and Kelly Arnett, MD, MPH, of the CU Department of Family Medicine. ACCORDS data analyst Bridget Mosley, MPH, and research associate Heather Smyth, PhD, also participated.

This story was published by the University of Colorado Cancer Center on September 17, 2024. It is republished with permission.