Here is the design of a clinical trial:

Official Title: Prebiopsy Magnetic Resonance Imaging in Men With Suspicion of Prostate Cancer - A Multi-centre Trial on Clinical Utility of IMPROD bpMRI in a Shared Decision Making Setting

Included conditions:
- Prostate Cancer

Study Armgroups:
- {'label': 'Control', 'type': 'NO_INTERVENTION', 'description': 'After IMPROD bpMRI all men undergo prostate biopsies. In men with Likert scores of 1-2, TRUS guided systematic biopsies are performed. In men with Likert 3-5 score, in addition to systematic biopsies, two targeted biopsies are taken from each lesion (up to two lesions).'}
- {'label': 'Intervention', 'type': 'EXPERIMENTAL', 'description': 'After IMPROD bpMRI prostate biopsies are performed according to shared decision-making by the treating urologist and the patient. If biopsies are to be performed, in men with IMPROD bpMRI likert scores of 1-2, 12-core systematic TRUS guided biopsies are performed and in men with Likert 3-5 score lesions systematic biopsies are performed and two targeted biopsies are taken from each lesion (up to two lesions). If biopsies are not performed, men are referred for a PSA follow-up.', 'interventionNames': ['Diagnostic Test: A shared decision making']}

Interventions:
- {'type': 'DIAGNOSTIC_TEST', 'name': 'A shared decision making', 'description': 'Based on prostate cancer risk calculation (age, usage of 5-ARI medication, baseline PSA, IMPROD bpMRI Likert, prostate volume) a shared decision making whether to perform prostate biopsies or not', 'armGroupLabels': ['Intervention']}

Primary Outcomes:
- {'measure': 'Gleason 4+3=7 prostate cancer, baseline', 'description': 'The proportion of men with clinically significant prostate cancer (Gleason 4+3 \\[ISUP grade group, the GGG, 3\\]) prostate cancer or higher) in the control and intervention arms after primary diagnostic pathway', 'timeFrame': 'baseline'}

Please estimate the sample size based on the assumption: 
Alpha level of 0.05, beta level of 0.2, and a dropout rate of 2%.
Sample size calculation
        The concept of sample size recalculation was brought up in protocol V.2.0 (4 January 2021). A two-stage sample size calculation was performed: first, an initial calculation before the start of the trial; second, a predetermined blinded re-estimation after the recruitment of the first 300 subjects.
        
          
            The estimation of the clinically significant prostate cancer rate was based on data from our previous prospective trials (the IMPROD and the multi-IMPROD).7 8 Using a clinically significant cancer rate of 25% in both arms, a non-inferiority margin of â8%, a beta level of 0.2 and an alpha level of 0.05, it was estimated that 600 subjects would be needed.
          
          
            The re-estimation of sample size is based on the observation that clinically significant prostate cancer is present in 20% of the first 300 subjects. Also, regarding the potential difference in clinically significant cancer rates between the arms, the sample size is evaluated in three different scenarios. Using a non-inferiority margin of â8%, a beta level of 0.2 and an alpha level of 0.05, the scenarios are as follows:
            
              
                with a rate of 20.0% in both arms, 624 participants will be needed.
              
              
                With rates of 20.5% (control arm) and 19.5% (intervention arm), 814 subjects will be needed.
              
              
                With rates of 21.0% (control arm) and 19.0% (intervention arm), 1104 subjects will be needed.
              
            
          
        
        It is decided that the final sample size will be calculated according to scenario b. Using a dropout rate of 2%, 830 subjects will be recruited. The recalculated sample size was implemented in the latest protocol amendment (V.2.1, 21 September 2021).