Here is the design of a clinical trial:

Official Title: A Randomized Controlled Pilot Study Assessing Feasibility and Impact of a Wilderness Program on Mental and Physical Health of Adolescent and Young Adult Cancer Survivors

Included conditions:
- Cancer

Study Armgroups:
- {'label': 'Wilderness program', 'type': 'EXPERIMENTAL', 'description': 'A one-week (8 days) wilderness program, 3-month online support, and a follow-up visit for four days.', 'interventionNames': ['Other: WAYA-Wilderness']}
- {'label': 'Holiday program (Attention control)', 'type': 'OTHER', 'description': 'A one-week (8 days) holiday program, 3-month online contact, and a follow-up visit for four days.', 'interventionNames': ['Other: WAYA-Holiday']}

Interventions:
- {'type': 'OTHER', 'name': 'WAYA-Wilderness', 'description': "The wilderness intervention includes challenging tasks in order to help participants' overcome and master new physical and psychological challenges in an unknown environment, with the idea to support self-efficacy, self-esteem, and ability to recover from adversity. The program is designed to encourage participants to connect with nature as to experience gratitude for the richness of the natural world, a sense of calmness and trust upon spending time in nature, and to be more physically active in nature.\n\nElements previously described Participants will continue in a three-month program at home (on-line supported) after the initial 8-days in order to empower participants to incorporate elements of the onsite wilderness program into their daily life. An individualized a plan for activities will be developed together with the participant.\n\nAfter three months, there will be a re-visit with follow up on outcome measures and reconnection.", 'armGroupLabels': ['Wilderness program']}
- {'type': 'OTHER', 'name': 'WAYA-Holiday', 'description': 'An attention control group (information in "Detailed description")', 'armGroupLabels': ['Holiday program (Attention control)']}

Primary Outcomes:
- {'measure': 'Feasibility - Participant Preferences', 'description': 'Participant Preferences (P-Pref) regarding intervention arms (no pref, slight pref, strong preference)', 'timeFrame': 'At prestudy screening - prior to inclusion'}
- {'measure': 'Feasibility - Participant expectations', 'description': 'A textual description of what participants would expect to experience from participation in either intervention group.', 'timeFrame': 'At prestudy screening - prior to inclusion'}
- {'measure': 'Feasibility - Participant willingness to be randomized', 'description': 'Willingness of participants to be randomized (Yes/No)', 'timeFrame': 'At prestudy screening - prior to inclusion'}
- {'measure': 'Feasibility - Time to recruitment', 'description': 'A planned n of 40 is planned and documentation of time to reach the goal will be made until predetermined number of participants are reached or max up till 18 months', 'timeFrame': 'Until predetermined number of participants are reached or max up till 18 months'}
- {'measure': 'Feasibility - Participant Adherence to Protocol', 'description': 'Adherence of the participants to the study protocol. A textual description of participant adherence based on observation and interviews documented in the participants study protocol', 'timeFrame': 'through study completion, an average of 1 1/2 year'}
- {'measure': 'Feasibility - Logistics and Burden', 'description': 'Logistics and Burden (for participants) to perform physical performance/fitness tests. A textual description of participant Log-BurdenPhysbased on observation and interviews documented in the participants study protocol', 'timeFrame': 'Through study completion, an average of 1 1/2 year'}
- {'measure': 'Feasibility - Logistics and willingness to complete all planned study-related questionnaires', 'description': 'Logistics and willingness to complete all planned study-related questionnaires. A textual description of participant Log-WillQuest based on observation and interviews documented in the participants study protocol', 'timeFrame': 'Through study completion, an average of 1 1/2 year'}
- {'measure': 'Feasibility - Adherence to three month at home program', 'description': 'The adherence of the participants to the three months at home program and transference of activities in this period. A textual description of participant adherence based on observation and interviews documented in the participants study protocol', 'timeFrame': 'up to three months'}
- {'measure': 'Feasibility - Occurrence of adverse events', 'description': 'Occurrence of adverse events during program execution. A textual description of occurence of AdvEvents based on observation and interviews documented in the participants study protocol.\n\nAdverse events will be coded according to the Medical Dictionary for Regulatory Activities (MedDRA) and analysed using preferred terms and allocation to system organ class. Safety of the interventions will be measured by analyzing number and type of adverse events reported.', 'timeFrame': 'up to three months'}

Please estimate the sample size based on the assumption: 
Recommendations of Whitehead et al
Sample size
        Based on the recommendations of Whitehead et al43 and an expected small to medium effect size for changes in quality of life, a sample size of 40 participants (n=20 per group) is chosen for this pilot study. A sample size of 20 participants in each group is also thought to generate sufficient interviews for the qualitative evaluation in the study.