Patient and public involvement in the design and conduct of a large, pragmatic observational trial to investigate recurrent, high-risk non-muscle-invasive bladder cancer.

Involving patients and other stakeholders in research ensures that it reflects the outcomes that matter most to them. This is especially important when research focuses on conditions in which patients face difficult decisions about treatment options. This article describes the key role that stakeholders played in shaping the Comparison of Intravesical Therapy and Surgery as Treatment Options for Bladder Cancer (CISTO) study. It compares treatments for recurrent noninvasive bladder cancer and describes how stakeholders were engaged to design and develop the study and the practices that supported their involvement.