Candidate for the Lee B. Lusted Student Prize Competition
Purpose: We aimed to elicit women’s responses to information about the nature and extent of overdiagnosis in screening mammography (detecting disease that would not present clinically during the woman’s lifetime) and explore how awareness of this largely unfamiliar issue may influence screening attitudes and intentions.
Methods: Fifty women aged 40-79 years with no personal history of breast cancer, varying in screening participation and educational background, participated in eight age-stratified focus groups. Each session included a consumer-friendly audiovisual presentation to explain overdiagnosis in screening mammography, incorporating different published estimates of its rate of occurrence (1-10%, 30%, and 50% of cancers diagnosed among regularly screened women), as well as evidence-based information on the mortality benefit of screening. Participants engaged in group discussions, guided by a pair of moderators, exploring their attitudes towards overdiagnosis, reactions to the overdiagnosis estimates, the influence of this information on screening intentions, and views about different strategies for communicating about screening. Discussions were audio-recorded, transcribed, and analysed thematically.
Results: As expected, prior awareness of overdiagnosis was limited. However, after questions were addressed and clarifications offered, most participants gained an understanding of this complex issue. Learning about overdiagnosis made some women perceive a need for more careful personal decision-making about screening, particularly if further research were to confirm the highest estimate (around 50%). In contrast, the estimates of 1-10% and 30% overdiagnosis had limited impact. Many women felt strongly committed to screening, regardless of the level of overdiagnosis. For some women, the information raised concerns not about whether to screen but rather whether to treat a screen-detected cancer or consider alternative approaches (e.g., ‘watchful waiting’). Most participants felt that the information presented was important and should be available to enable women to make informed choices, although many also wanted to be encouraged to screen.
Conclusions: Women had diverse responses to overdiagnosis and the different estimates of its magnitude. Some women would rethink their screening intentions at the 50% estimate but few at the lower or intermediate estimates. We found that lay women from a range of socioeconomic backgrounds can be informed about overdiagnosis, and that women valued the information. Providing information about overdiagnosis would facilitate better informed decisions about mammography screening. Future research should quantify any impact such information may have on screening participation.