Here is the design of a clinical trial:

Official Title: RAdiotherapy RElated Skin Toxicity: a Reminder App to Reduce Radiation Dermatitis Rates in Patients with Head-and-Neck Cancer

Included conditions:
- Radiation Dermatitis
- Radiation-induced Oral Mucositis

Study Armgroups:
- {'label': 'Standard Care supported by a Reminder App (Arm A)', 'type': 'EXPERIMENTAL', 'description': 'Treatment with Standard Care supported by a Reminder App, starting at the beginning of radiotherapy.', 'interventionNames': ['Device: mobile application (reminder app)']}
- {'label': 'Standard Care alone (Arm B)', 'type': 'ACTIVE_COMPARATOR', 'description': 'Treatment with Standard Care alone, starting at the beginning of radiotherapy.', 'interventionNames': ['Device: mobile application (reminder app)']}

Interventions:
- {'type': 'DEVICE', 'name': 'mobile application (reminder app)', 'description': "This app will remind the patients four times a day to perform skin and mouth care. Instructions are given how to properly perform skin and mouth care. The patients may postpone each required care procedure for up to 2 hours. Finally, the patients are asked to state for each procedure whether or not they performed it. To increase the patients' motivation, they will earn points for each successfully performed care procedure.", 'armGroupLabels': ['Standard Care alone (Arm B)', 'Standard Care supported by a Reminder App (Arm A)']}

Primary Outcomes:
- {'measure': 'Rate of radiation dermatitis grade ≥2', 'description': 'at least moderate radiation-induced skin toxicity such as erythema and desquamation', 'timeFrame': 'until 60 Gy of radiotherapy'}

Please estimate the sample size based on the assumption: 
Chi-square test, two-sided significance level of 5%, statistical power of 80%, and a 5% dropout rate.
Sample size {14}
        This study aims to show that standard skin care supported by a reminder app is superior to standard skin care alone regarding the avoidance of gradeââ¥â2 dermatitis up to 60 Gy in patients irradiated for locally advanced head-and-neck cancers.
        The null hypothesis of equal gradeââ¥â2 dermatitis rates in both groups is tested against the two-sided alternative hypothesis of unequal dermatitis rates. The calculation of the sample size considered the following assumptions:
Application of a chi-square testTwo-sided significance level of 5%Rates of gradeââ¥â2 dermatitis of 86â92% with standard care alone according to previous studiesAssumption of a gradeââ¥â2 dermatitis rate of 85% in the standard care alone group (âworst-caseâ)Clinical importance of the impact of the reminder appâ=âreduction of gradeââ¥â2 dermatitis by 20%Statistical power of 80%
        When considering these assumptions, 80 patients are needed per arm within the full analysis set. Assuming that 5% of the recruited patients will not qualify for the full analysis set, 168 patients need to be randomized.