Here is the design of a clinical trial:

Official Title: Randomized Clinical Trial of the MyPal ePRO-based Early Palliative Care System in Adult Patients With Hematologic Malignancies

Included conditions:
- Chronic Lymphocytic Leukemia
- Myelodysplastic Syndromes

Study Armgroups:
- {'label': 'Experimental arm', 'type': 'EXPERIMENTAL', 'description': 'Administration of the MyPal ePRO system', 'interventionNames': ['Other: Administration of the MyPal ePRO system']}
- {'label': 'Standard care arm', 'type': 'NO_INTERVENTION', 'description': 'No further intervention besides standard palliative care approach if needed'}

Interventions:
- {'type': 'OTHER', 'name': 'Administration of the MyPal ePRO system', 'description': 'Patients will be asked to complete self-report questionnaires at baseline, and every month for the first six months and at 12-month follow-up', 'armGroupLabels': ['Experimental arm']}

Primary Outcomes:
- {'measure': 'Improvement in EORTC Quality of Life Questionnaire (QLQ)-C30 General Questionnaire', 'description': 'The primary objective is to determine whether - compared to standard care - the MyPal-ADULT intervention can lead to improved QoL as evidenced by statistically significant higher scores in EORTC Quality of Life Questionnaire (QLQ)-C30 General Questionnaire', 'timeFrame': 'through study completion, an average of 1 year'}
- {'measure': 'Improvement in EuroQol (EQ)-five dimensions (5D)', 'description': 'The primary objective is to determine whether - compared to standard care - the MyPal-ADULT intervention can lead to improved QoL as evidenced by statistically significant higher scores in EuroQol (EQ)-five dimensions (5D).', 'timeFrame': 'through study completion, an average of 1 year'}

Please estimate the sample size based on the assumption: 
A significance level of 0.05, power over 90%, attrition rate of 20%, and missing data rate of 30%.
Sample size calculation
        Assuming relatively acceptable values for the attrition rate (ie, 20%) and the missing data (ie, 30%), the sample size analysis concluded that 300 recruited patients with CLL or MDS at any ratio providing one measure at enrolment (baseline) and seven repeated measures (at months 1, 2, 3, 4, 5, 6 and 12) are sufficient for the power of the intended statistical testing to be over 90% in all cases, given (a) a 0.05 significance level and (b) an effect size of 0.2; the employed value of the effect size was based on a priori knowledge of the domain.