Children with medulloblastoma, an aggressive brain tumor, require prolonged and complex multimodal therapy. Their primary parental caregivers bear the main responsibility for ensuring treatment adherence, yet the psychological toll on these caregivers may undermine their ability to follow prescribed regimens. This study investigates whether multidimensional parental distress predicts overall treatment adherence in this population, and which specific distress domains are most strongly associated with poor adherence.

Parental distress-including depression, anxiety, and posttraumatic stress-is common among parents of children with cancer and may interfere with their ability to manage complex treatment regimens. However, no study has specifically examined whether parental distress predicts treatment adherence in children with recurrent medulloblastoma, a devastating brain tumor with a poor prognosis and no standard treatment protocol.

This prospective longitudinal cohort study aims to investigate whether parental distress is a significant predictor of treatment adherence in children with recurrent medulloblastoma. A total of 450 parent-child dyads will be enrolled across 4 tertiary pediatric oncology centers. Children must have a confirmed diagnosis of recurrent medulloblastoma and be receiving active treatment. Parents (primary caregivers) will complete validated questionnaires at baseline assessing depression, anxiety, stress, and trauma-related distress using the DASS-21 and IES-R. Treatment adherence will be monitored over a 12-month follow-up period using electronic medication monitoring caps, clinic attendance records, and parent-reported medication logs.

The primary outcome is the proportion of prescribed chemotherapy doses taken (treatment adherence rate). Secondary outcomes include trajectories of adherence over time and the relationship between specific dimensions of parental distress (depression, anxiety, stress, posttraumatic stress) and adherence patterns. The study will also examine whether child clinical factors (e.g., molecular subgroup, prior treatment history) and family demographic factors moderate this relationship.

Findings from this study may inform the development of targeted psychosocial interventions to support distressed parents and improve treatment adherence-and ultimately clinical outcomes-in this vulnerable pediatric population. Participants can expect to be enrolled in the study for approximately 12 months.

Inclusion Criteria(Children):

• Diagnosis of medulloblastoma with documented recurrence (radiographic or histopathological confirmation)
• Age ≤ 18 years at enrollment
• Currently receiving active treatment for recurrent disease
• Life expectancy ≥ 3 months

Inclusion Criteria (Parents/Caregivers):

• Primary caregiver responsible for medication administration and treatment coordination
• Age ≥ 18 years
• Able to read and understand study materials in [English]
• Willing to complete study assessments

Exclusion Criteria:

• Child receiving exclusively palliative/hospice care
• Parent with severe psychiatric illness or cognitive impairment preventing informed consent or questionnaire completion
• Child enrolled in another interventional trial that would confound adherence measurement

Parent-child dyads where child has recurrent medulloblastoma and is receiving active treatment

De-identified individual participant data will be available upon reasonable request to the corresponding author and institutional approval.