Here is the design of a clinical trial:

Official Title: PRO-ACTIVE: Comparing The Effectiveness of Prophylactic Swallow Intervention for Patients Receiving Radiotherapy for Head and Neck Cancer

Included conditions:
- Dysphagia

Study Armgroups:
- {'label': 'RE-ACTIVE', 'type': 'ACTIVE_COMPARATOR', 'description': 'Reactive intervention started promptly if/when dysphagia is identified (RE-ACTIVE)', 'interventionNames': ['Behavioral: RE-ACTIVE']}
- {'label': 'PRO-ACTIVE EAT', 'type': 'ACTIVE_COMPARATOR', 'description': 'Early low intensity proactive intervention started before RT commences', 'interventionNames': ['Behavioral: PRO-ACTIVE EAT']}
- {'label': 'PRO-ACTIVE EAT + EXERCISE', 'type': 'ACTIVE_COMPARATOR', 'description': 'Early high intensity proactive intervention started before RT commences', 'interventionNames': ['Behavioral: PRO-ACTIVE EAT + EXERCISE']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'RE-ACTIVE', 'description': 'Reactive intervention started promptly if/when dysphagia is identified', 'armGroupLabels': ['RE-ACTIVE']}
- {'type': 'BEHAVIORAL', 'name': 'PRO-ACTIVE EAT', 'description': 'Early low intensity proactive intervention started before RT commences', 'armGroupLabels': ['PRO-ACTIVE EAT']}
- {'type': 'BEHAVIORAL', 'name': 'PRO-ACTIVE EAT + EXERCISE', 'description': 'Early high intensity proactive intervention started before RT commences', 'armGroupLabels': ['PRO-ACTIVE EAT + EXERCISE']}

Primary Outcomes:
- {'measure': 'Duration of feeding tube dependence', 'description': 'Effectiveness will be measured based on duration of feeding tube dependency (count of days from end of radiotherapy to last feeding tube use within the 12-month study period)', 'timeFrame': 'Baseline - 12 months'}

Please estimate the sample size based on the assumption: 
The type 1 error probability is set at 0.05 (two-sided) for all comparisons. The power is set at 80% for detecting the specified effect sizes. The attrition factor is set at 5% for the primary endpoint and feeding tube dependence at 3-months, and 26% for secondary analyses requiring clinical visits and survey responses.
Sample size calculation
        Sample size calculations, based on a 2-sample t-test, assume 952 patients enrolled with 1:4 allocation to RE-ACTIVE (Arm 1, nÂ =â190) and PRO-ACTIVE arms (Arms 2 and 3, nÂ =â381 per group). The attrition factor is set at 5% because the primary endpoint can be ascertained without clinical encounter. Thus, the resultant sample size estimated is 180 in Arm 1, 361 in Arm 2, and 361 in Arm 3. For the primary comparison (Hyp 1.1) of Arm 1 (nÂ =â180) versus the combined Arms 2 and 3 (nÂ =â722), assuming ITT analysis with type 1 error probability of 0.05 (two-sided) yields 80% power to detect a small effect size of .23 SD for duration of feeding tube use. For the analysis of Hyp 1.2 in the gate-keeper approach, we will compare intensity of PRO-ACTIVE therapies (Arm 2 versus Arm 3, nÂ =â361 per group), assuming type 1 error probability of 0.05 (two-sided), we have 80% power to detect again a small effect size of 0.21 SD for the primary endpoint of feeding tube duration. We expect the t-test will not be sufficient as the primary analysis given it does not allow for covariate adjustment. Therefore, we will apply the multiple linear regression model as the primary analysis for Aim 1. The power calculation conducted assuming t-tests for analysis of hypotheses 1.1 and 1.2 and deriving a sample of 952 patients remain sufficient for the linear model because by adjusting for variables associated with the mean response, the distribution of the residuals is expected to improve. Therefore, the power for the same hypothesized difference in the primary outcome attributed to treatment in the regression framework will be at least as much as for that for the t-test.
        For the secondary analysis (Aim 2) in the gate-keeper approach, we will compare intensity of PRO-ACTIVE therapies (Arm 2 versus Arm 3, nÂ =â361 per group), assuming type 1 error probability of 0.05 (two-sided), we have 80% power to detect again a small effect size of 0.24 SD for PROs and VFS measures. The attrition factor for the secondary analysis is set at 26% because they are more prone to attrition due to required clinical visits and survey responses required from participants. As an exception, feeding tube dependence at 3-months uses an attrition factor of 5%, for the same rationale as the primary endpoint.