Here is the design of a clinical trial:

Official Title: Evaluating Omitting of Internal Mammary Irradiation Among Early Stage Intermediate Risk (N1) Breast Cancer Patients According to Clinical-genomic Model: an Open Label, Non-inferior Randomized Controlled Trial

Included conditions:
- Breast Cancer

Study Armgroups:
- {'label': 'experimental group', 'type': 'EXPERIMENTAL', 'description': 'whole breast/chest wall irradiation + SVC irradiation', 'interventionNames': ['Radiation: omit of IMI group']}
- {'label': 'controlled group', 'type': 'ACTIVE_COMPARATOR', 'description': 'whole breast/chest wall irradiation + IMI+SVC irradiation', 'interventionNames': ['Radiation: IMI group']}

Interventions:
- {'type': 'RADIATION', 'name': 'omit of IMI group', 'description': 'clincial high risk breast （≥2 risk factors）patients with 18-gene low risk an indication for regional nodal irradiation will received 2 Gy for 25 fractions to chest wall or whole breast and supraclavicular lymph nodes irradiation and sequential tumor bed boost of 2 Gy for 5 fractions following breast conserving surgery.', 'armGroupLabels': ['experimental group']}
- {'type': 'RADIATION', 'name': 'IMI group', 'description': 'clincial high risk breast （≥2 risk factors）patients with 18-gene low risk an indication for regional nodal irradiation will received 2 Gy for 25 fractions to chest wall or whole breast and supraclavicular lymph nodes irradiation and sequential tumor bed boost of 2 Gy for 5 fractions following breast conserving surgery.', 'armGroupLabels': ['controlled group']}

Primary Outcomes:
- {'measure': '2-year event-free survival', 'description': 'any recurrence,distant metastasis or death in 2 years', 'timeFrame': '2 years'}

Please estimate the sample size based on the assumption: 
Statistical power of 80%, an alpha level of 0.025 (one-sided), and an anticipated enrolment period of 24 months.
Power and sample size calculation
          The power and sample size are calculated according to the hypothesis that the 5-year event-free survival of omitting IMNI group is non-inferior to those patients treated with comprehensive RNI with IMNI. According to survival outcome of pN1 breast cancer in our institute, the 5-year event free survival (EFS) is estimated to be 91% for the control and 81% for experimental groups, respectively. The permissible limit for HR is 2.30, with statistical power of 80%, an alpha level of 0.025 (one-sided). With an anticipated enrolment period of 24Â months, a total sample size of 208 patients is estimated to be needed. To compensate for eligible patients, the targeted number of patients is set at 214.