Here is the design of a clinical trial:

Official Title: A Prospective and Longitudinal Cohort Study Assessing Mental wellbeIng and Quality of Life in Prostate Cancer - the MIND-P Study

Included conditions:
- Prostate Cancer

Study Armgroups:
- {'label': 'Radical Prostatectomy', 'description': 'Participants undergoing any curative surgical treatment option for prostate cancer irregardless of approach (open, laparoscopic or robotic)'}
- {'label': 'Active Surveillance', 'description': 'Participants undergoing active surveillance as the management option for prostate cancer as defined by regular surveillance attendance at the primary treating site.'}
- {'label': 'Hormone Monotherapy', 'description': 'Participants undergoing medical hormone therapy (Antiandrogens and Gonadotropin-releasing hormone (GnRH) agonists or antagonists) or surgical castration (e.g. orchidectomy) options as the primary treatment for prostate cancer.'}
- {'label': 'Radical Radiotherapy', 'description': 'Participants undergoing primary radiotherapy treatment for prostate cancer irregardless of delivery methods (e.g. External beam radiation therapy or brachytherapy).'}

Interventions:

Primary Outcomes:
- {'measure': 'Mean difference of mental wellbeing measures between four management groups', 'description': 'Mental wellbeing validated tools scores including Patient Health Questionnaire-9 (PHQ-9), Generalised Anxiety Disorder-7 (GAD-7), Body Image Scale, Fear of Recurrence Scale and Masculine Self-Esteem Prostate Cancer-Related Quality of Life (PC-QOL) Subset Scale', 'timeFrame': 'Baseline, 3, 6, 9 and 12 months post diagnosis'}

Please estimate the sample size based on the assumption: 
One-way ANOVA, power of 0.8, alpha value of 0.05, dropout rate of 25%.
Sample size
        Target sample size calculations are based on the primary aim and outcome of the study evaluating mean differences between different treatment cohorts. This was conducted for hypothesis testing against minimal clinically significant difference (MCSD) of the five mental wellbeing measures of interest, as previously reported in the literature. This was calculated utilising a one-way ANOVA across the four cohorts. Common standard deviation (SD) derived from the literature, or previous pilot data from a small cross-sectional sample were also used to subsequently calculate the effect size f value, with a power of 0.8 and an alpha value of 0.05 utilised. G*Power Software V3.1 [30] was used to calculate the required sample sizes. The largest required sample size across the five mental wellbeing measures was used as the required minimal sample size.
        
          
            PHQ-9 âMCSD of 5 [31], SD of 3.49 (pilot data)
          
          
            GAD 7 âMCSD of 5 [32], SD of 3.49 (pilot data)
          
          
            FCR7 âMCSD of 10, SD 7.01 [24]
          
          
            BISâNo clear MCSD published in literature [33], use of 10 as cut off for significant symptoms [25], SD of 3.93 (pilot data)
          
          
            Masculine Self-Esteem MCSD of 9.8 [34], SD of 15.79 [35]
          
        
        Sample size calculations utilising the above values revealed a maximum requirement of 232 participants (58 per cohort) using the PC-QOL Masculine Self-Esteem Scale. Assuming a reasonable dropout rate of 25%, a requirement of 75 participants per cohort was set to give an overall target sample of 300 participants. During recruitment, individual treatment cohorts of these sizes will be targeted, with a gradual stop in recruitment across these different cohorts to gain sizes of groups as close to equal as possible. However, due to likely unequal dropout rates and some crossover to different treatment arms during follow up (e.g. those undergoing surveillance subsequently undergoing radical treatment) it is likely some disparity in cohort sizes will exist. These would subsequently require consideration within analysis and conclusions drawn from study results if any individual cohort contains fewer than the minimum sample size described above.