Lancet: Women informed about risks of overdiagnosis less likely to get mammogram

Women who are informed about the risks of overdiagnosis and overtreatment when it comes to mammography are less likely to undergo a breast cancer screening exam, according to a new study in the journal Lancet.

In the study, led by Kirsten McCaffery, PhD, of the University of Sydney, researchers looked at the effect that including information on over-diagnosis and overtreatment in decision support materials could have on women making decisions about mammography screening.

The study cohort included 879 women between the ages of 48 and 50 who had not had a mammogram in the previous two years and didn’t have a personal or strong history of breast cancer. The women were randomly assigned to an intervention decision-aid group (consisting of evidence-based explanatory and quantitative information on overdetection, breast cancer mortality reduction and false positives) or a control decision aid (including information on breast cancer mortality reduction and false positives). 

The researchers found that women in the intervention decision-aid group had more knowledge about breast cancer screening and were more likely to make an informed choice whether to be screened.

While women in the intervention decision group still had positive attitudes towards breast cancer screening, those attitudes were “significantly” less favorable than the attitudes of the women in the control decision group. In addition, fewer women in the intervention decision group intended to be screened for breast cancer.

"A health system centered around the individual should assist decision-making that incorporates a woman's values and preferences, irrespective of whether her eventual choice is to screen or not,” said McCaffery in a statement. "Therefore, 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."