Towards a public-facing version of the CanRisk tool: Co-designing, developing and evaluating MyCanRisk

The CanRisk tool allows healthcare professionals to calculate validated multifactorial estimates of breast, ovarian, and prostate cancer risk. To support patient involvement in risk assessment, we co-designed a public-facing tool, MyCanRisk, which allows patients to collect and share risk information in advance of a clinical appointment, without generating risk estimates. This study describes the user-centred development of MyCanRisk and its initial evaluation. Development involved co-design workshops with patients, public contributors, healthcare professionals, and researchers, followed by iterative accessibility and usability testing against WCAG 2.2. Evaluation used a multi-methods design: 51 women with a family history of breast cancer completed MyCanRisk and, approximately two weeks later, a structured clinical-style interview. Agreement in risk categorisation was assessed using Cohen's kappa. Semi-structured interviews with a purposive subsample (n=15) explored user experiences. MyCanRisk was perceived as accessible and easy to use. Agreement between MyCanRisk and structured interviews for risk categorisation was substantial (κ = 0.81, 95% CI 0.65-0.97). Discrepancies mainly reflected difficulties recalling detailed family history, such as ages at diagnosis and dates of birth/death. Participants valued the stepwise flow and asynchronous completion but reported challenges when their knowledge was incomplete. Suggested improvements included options to record approximate or unknown data and greater flexibility to update submissions. MyCanRisk has the potential to reduce data collection burden during clinical encounters, support patient preparation for risk assessment, and streamline cancer risk assessment pathways. With further refinement and testing in more diverse populations, it may facilitate earlier identification of individuals at increased cancer risk.