The ‘Trial within Cohorts’ design (TwiCs). After ethical approval for an interventional TwiCs study, eligible patients are selected from the cohort. Only patients who have given informed consent for potential participation in TwiCs upon entry in the PRO-RCC cohort are eligible for selection. After selection, eligible patients are randomized to the control or the intervention arm. Before inclusion in the intervention arm, separate informed consent has to be obtained from each patient. Patients in the control arm receive standard of care similar to the rest of the cohort and do not receive additional information. These patients have consented not to be notified of randomization in a TwiCs control arm, as part of their consent to TwiCs participation upon entry in the PRO-RCC cohort
