Evaluation of a widely available patient decision aid for the treatment of prostate cancer.

•A decision aid for early-stage prostate cancer treatment was made widely available.•993 users provided usage data and 168 of them completed a usability assessment.•Users varied in the components of the aid that they used.•Overall, users found the aid helpful and would recommend it to other patients.•Variation in patterns of use was not associated with differences in either outcome.