Women’s views on overdiagnosis in breast cancer screening: a qualitative study

OBJECTIVE To elicit women's responses to information about the nature and extent of overdiagnosis in mammography screening (detecting disease that would not present clinically during the woman's lifetime) and explore how awareness of overdiagnosis might influence attitudes and intentions about screening. DESIGN Qualitative study using focus groups that included a presentation explaining overdiagnosis, incorporating different published estimates of its rate (1-10%, 30%, 50%) and information on the mortality benefit of screening, with guided group discussions SETTING Sydney, Australia PARTICIPANTS Fifty women aged 40-79 years with no personal history of breast cancer and with varying levels of education and participation in screening. RESULTS Prior awareness of breast cancer overdiagnosis was minimal. Women generally reacted with surprise, but most came to understand the issue. Responses to overdiagnosis and the different estimates of its magnitude were diverse. The highest estimate (50%) made some women perceive a need for more careful personal decision making about screening. In contrast, the lower and intermediate estimates (1-10% and 30%) had limited impact on attitudes and intentions, with many women remaining committed to screening. For some women, the information raised concerns, not about whether to screen but whether to treat a screen detected cancer or consider alternative approaches (such as watchful waiting). Information preferences varied: many women considered it important to take overdiagnosis into account and make informed choices about whether to have screening, but many wanted to be encouraged to be screened. CONCLUSIONS Women from a range of socioeconomic backgrounds could comprehend the issue of overdiagnosis in mammography screening, and they generally valued information about it. Effects on screening intentions may depend heavily on the rate of overdiagnosis. Overdiagnosis will be new and counterintuitive for many people and may influence screening and treatment decisions in unintended ways, underscoring the need for careful communication.