Women who understand the risk of over-detection and over-diagnosis associated with mammography screening are less likely to have a breast screening test, new research has found. “Mammography screening can reduce breast cancer deaths but most women are unaware that inconsequential disease can also be detected by screening, leading to over-diagnosis and over-treatment,” said study author Kirsten McCaffery from the University of Sydney.
Over-detection and over-diagnosis refer to the diagnosis and treatment of breast cancer that would not have presented clinically during a woman’s lifetime. Such a diagnosis, and the resulting over-treatment, can harm women physically and emotionally. The study involved 879 women aged 48-50 years. The women who participated in the study had not had mammography in the past two years and did not have a personal or strong family history of breast cancer.
The researchers found that compared to controls, in women provided with decision support containing explanatory and quantitative information about over-detection, significantly fewer women intended to be screened for breast cancer. The intervention decision aid contained evidence-based information about important outcomes of breast screening over 20 years, compared with no screening that is, breast cancer mortality reduction, over-detection, and false positives.
The control version omitted all content about over-detection but was otherwise identical to the intervention decision aid. The study “underlines the ethical imperative for women to have clear decision support materials so that they can make more informed decisions about whether they want to have a breast screening mammogram,” McCaffery added.