Here is the design of a clinical trial:

Official Title: What is the Effectiveness and Safety of Mirtazapine Versus Escitalopram in Alleviating Cancer-associated Poly-symptomatology (MIR-P)? A Mixed-method Randomized Controlled Trial Protocol

Included conditions:
- Cancer
- Neoplasms
- Neoplasm Metastasis

Study Armgroups:
- {'label': 'Oral mirtazapine', 'type': 'EXPERIMENTAL', 'description': 'Arm 1 patients will be treated using a daily mirtazapine treatment. Treatment will be taken on the evening. Treatment will be initiated at 15 mg daily and gradually increased depending on symptom control and side effects. Treatment doses will be adapted for old patients and those with liver failure.', 'interventionNames': ['Drug: Mirtazapine']}
- {'label': 'Oral escitalopram', 'type': 'ACTIVE_COMPARATOR', 'description': 'Arm 2 patients will be treated using a daily escitalopram treatment. Treatment will be taken in the morning. Treatment will be initiated at 10 mg daily and gradually increased depending on symptom control and side effects. Treatment doses will be adapted for 5 mg for old patients.', 'interventionNames': ['Drug: Escitalopram']}

Interventions:
- {'type': 'DRUG', 'name': 'Mirtazapine', 'description': 'Orally disintegrating tablets of mirtazapine introduced at the dose of 15 mg and increased up to 45 mg per day during 56 days.\n\nDoses escalation: based on symptom management and side effect assessment.', 'armGroupLabels': ['Oral mirtazapine']}
- {'type': 'DRUG', 'name': 'Escitalopram', 'description': 'Orally disintegrating tablets of escitalopram introduced at the dose of 10 mg (or 5 mg for patients older than 65) and increased up to 20 mg per day during 56 days.\n\nDoses escalation: based on symptom management and side effect assessment.', 'armGroupLabels': ['Oral escitalopram']}

Primary Outcomes:
- {'measure': 'Global health status score', 'description': 'The Global Health Status will be calculated from the specific subscale included in the EORTC-QLQ-C30 scale.\n\nThe difference between baseline and the end-point (day 56) will be the primary judgment criteria. A 4 to 8 points difference between baseline and endpoint will be considered as a mild difference, and a difference over 8 points will be considered as a moderate difference.', 'timeFrame': 'At baseline and day 56'}

Please estimate the sample size based on the assumption: 
Bilateral test, alpha risk of 0.05, power of 0.8, and an attrition rate of 20%.
Sample Size
        Based on an expected standard deviation of 26 in our primary outcome (The Global health Status), and considering a correlation of 0.5 between inclusion and day 56 (corresponding in a standard deviation of the variation of the GHS score of 26 between baseline and day 56), and expecting a moderately clinically significant difference of 8 points between groups, it will be necessary to include 418 participants (bilateral test, alpha risk of 0.05, power of 0.8, attrition 0.2).
        Considering the risk of lost to follow-up due to our population global condition, we considered an attrition rate of 20% when calculate the sample size.