Fewer women opt for mammography screening when informed of overdiagnosis risk

Providing women with more comprehensive information about overdiagnosis as it relates to mammography screening can help them make an informed choice, which might mean a decision to forgo screening altogether, according to an Australian study published online Feb. 18 in The Lancet.

“Momentum is shifting from uninformative and persuasive approaches to screening communication to clear and balanced information, giving people the opportunity to make informed choices based on their assessment of the trade-offs between potential outcomes,” wrote study authors Jolyn Hersch, MApplSc, of the University of Sydney, and colleagues.

Most women are unware of the risk of overdiagnosis and overtreatment, explained the authors. To test whether including more information about such risks in a decision aid would help women make informed choices, Hersch and colleagues conducted a community-based, randomized controlled trial in New South Wales in which women ages 48 to 50 were randomly given one of two decision aids. Both versions of the decision aid, which was in the format of a short booklet, contained information about breast cancer deaths and the risk of false positives, but only the intervention decision aid contained data for overdetection and overdiagnosis.

Between January and July 2014, the outcomes of 409 women in the intervention group and 408 controls were analyzed, and the authors found 24 percent of the women in the intervention group and 15 percent in the control group made an “informed choice,” which was assessed based on the participant’s understanding of mammography benefits and risks during a follow-up phone interview.

The decision aids did not raise anxiety levels among the participants, according to Hersch and colleagues, but they did seem to change some attitudes regarding screening. Fewer women in the intervention group expressed positive attitudes toward screening, and while 87 percent of controls indicated an intention to screen, only 74 percent of the intervention group intended to be screened.

“Our study shows that women can incorporate overdetection information into their reasoning about screening, thereby improving the quality of their decisions,” wrote the authors. “Our results underscore the importance of striving to meet the ethical responsibility to adequately inform women and help them make screening decisions according to their informed preferences.”

In an accompanying editorial, Minna Johansson, a postgraduate student at the University of Gothenburg in Sweden, and John Brodersen, PhD, of the University of Copenhagen, wrote that the study from Hersch and colleagues was a refreshing change from the “paternalistic discourse” typical in screening research. They stressed that information on harms as well as benefits should be included in invitations to screening programs, and there should be acknowledgment that nonparticipation might be just as rational as participation.

“This shift of perspective, from paternalism to respect for women's autonomy, is one important step towards an approach consistent with contemporary ethical values,” wrote Johansson and Brodersen.