Clinical Trial Sample Size Calculation

I need assistance calculating the sample size for a clinical trial for my thesis in Medical Sciences. The primary outcome of our study is the comparison of treatments.

Requirements:
- Expertise in statistical methods for clinical trials
- Experience in sample size determination
- Knowledge of parameters relevant to treatment comparison

Ideal Skills:
- Advanced statistics
- Familiarity with clinical trial design
- Proficiency in statistical software (e.g., SAS, R)

Please provide a detailed methodology and any assumptions made during calculations.