Here is the design of a clinical trial:

Official Title: A Phase 2 Study of SBRT for Squamous Cell Carcinoma of the Head and Neck

Included conditions:
- Head and Neck Neoplasms
- Squamous Cell Carcinoma
- Squamous Skin Carcinoma

Study Armgroups:
- {'label': 'Stereotactic Body Radiotherapy (SBRT)', 'type': 'EXPERIMENTAL', 'description': 'The dose prescribed in the study will be 45Gy in 5 fractions, delivered once every 3-4 days, such that treatment is completed within 15 days. (e.g. treatment given on Monday/Thursday/Mon/Thurs/Mon) (Exceptions: treatment duration of up to 18 days will be allowed to account for cancer centre closures and unforeseen patient issues.)', 'interventionNames': ['Radiation: Stereotactic Body Radiotherapy (SBRT)']}

Interventions:
- {'type': 'RADIATION', 'name': 'Stereotactic Body Radiotherapy (SBRT)', 'description': '45 Gy in 5 fractions delivered once every 3-4 days', 'armGroupLabels': ['Stereotactic Body Radiotherapy (SBRT)']}

Primary Outcomes:
- {'measure': 'Tumour response rate', 'description': 'Tumour response rate defined as complete or partial response according to Tumour response rate will be defined by RECIST 1.1 criteria', 'timeFrame': 'The best overall response across all time points during the study period - up to 24 months after completion of SBRT.'}

Please estimate the sample size based on the assumption: 
The significance level (α) is 0.10, and the power (β) is 0.10. The true α is 0.097 and the true β is 0.096. The probability of termination at the end of stage I is 0.467.
Sample size calculation and assumptions
        Up to a total of 38 patients will participate in this single institution, single arm, phase 2 study. Based on prior research, the response rate for patients treated using theâ0â7-21â regimen was 82%, however, 6-month progression-free survival was only 39%. Given the expected relative minimal toxicity and ease of treatment using this regimen, a similar response rate of around 80% would be of considerable interest, while a response rate of 60% or lower would indicate that there would not be any interest in studying this regimen further. Hence, for sample size calculations, it will be assumed that H0: pâ=â60% versus HA: pâ=â80%, with Î±â=â0.10 and Î²â=â0.10. Using the Simon optimal two-stage design, 11 patients will be recruited in the first stage. If 6 or less patients have a response, the study will be stopped at the end of stage I, however, if 7 or more patients have a response the study will continue to stage II, in which an additional 27 patients (for a total of 38) will be recruited. At the end of stage II, if 26 or less patients have a response, then H0 will be accepted and the treatment regimen deemed not worthy of further study, however, if 27 or more patients have a response, the treatment regimen will be recommended for further study in phase III. The true Î±â=â0.097 and Î²â=â0.096 for this design, with a probability of termination at the end of stage I of 0.467.