Here is the design of a clinical trial:

Official Title: A Study Evaluating Effect of Smart Phone App-based Human Coaching Program on QOL in Patients Who Underwent Gastrectomy for Stage I Gastric Cancer

Included conditions:
- Stage I Gastric Cancer

Study Armgroups:
- {'label': 'Smart phone app group', 'type': 'EXPERIMENTAL', 'description': 'Patients used smart phone app based human coaching program for 3 months postoperatively.', 'interventionNames': ['Behavioral: smart phone app based human coaching program']}
- {'label': 'Nutritional consultation group', 'type': 'ACTIVE_COMPARATOR', 'description': 'Patients have two consulting with clinical nutritionist at 1 month and 3 months postoperatively.', 'interventionNames': ['Behavioral: smart phone app based human coaching program']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'smart phone app based human coaching program', 'description': '1. experimental arm\n\n   * 1:1 coaching using smart phone app\n   * Patients are provided several articles about postoperative care (symptom management, diet, and exercise) in the app.\n   * Patients are encouraged to report their diet diaries and exercise everyday by the coach.\n   * Patients can ask to the coach using the app and the coach answer when they check them.\n2. Comparator arm - Patient have consulting with clinical nutritionist at 1 month and 3 months postoperatively.', 'armGroupLabels': ['Nutritional consultation group', 'Smart phone app group']}

Primary Outcomes:
- {'measure': 'Eating restriction score (XEatR) at 3 months postoperatively', 'description': 'Eating resection scale is calcuated according to the following equation.\n\n1. Add questionnaire items 41,42, 43 and 46 and divide this sum by the number of items (4):\n\n   EatR = (Q41+Q42+Q43+Q46)/4\n2. Carry out a linear transformation to convert to a 1-100 scale:\n\nXEatR = (EatR-1)\\*100/3\n\nThe 4 items are belong to European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ) STO22.\n\nEach item has a value among 1, 2, 3, and 4 according to the answer and the scale score has a value ranging 0 (minimum) to 100 (maximum).\n\nHigher scores mean having more symptom and worse quality of life.', 'timeFrame': '3 months postoperatively'}

Please estimate the sample size based on the assumption: 
Type I error of 0.05, 80% statistical power, 1:1 enrolment ratio, and a 30% dropout rate.
Sample size
        The sample size was calculated based on the results of our pilot study and previous QoL studies which evaluated EORTC QLQ-STO22. In this study, the primary outcome is the eating restriction scale score of the EORTC QLQ-STO22, which was 30 points at postoperative 1 month in the pilot study. We also assume an intergroup difference of 5 points and standard deviation of 10 based on the results of previous QoL studies, yielding an effect size of 0.5 [14â17]. Given a type I error of 0.05, 80% statistical power, and 1:1 enrolment ratio, 126 participants were calculated using a 2-tailed t-test. Allowing for an 30% of dropout rate based on the results of the pilot study, we planned to recruit 180 participants (90 in each group) for this study.