High-Dimensional Mediation Analysis with Network Mediators: Applications to Pediatric Acute Lymphoblastic Leukemia

Area of Science:

• Neuroscience
• Oncology
• Biostatistics

Background:

• Acute lymphoblastic leukemia (ALL) is a common childhood cancer.
• Survivors often experience long-term neurocognitive deficits.
• Understanding the mechanisms behind these deficits is crucial for developing interventions.

Purpose of the Study:

• To investigate the mechanisms of treatment-related neurocognitive side effects in pediatric ALL survivors.
• To utilize brain connectivity network data from the TOTXVI clinical trial.
• To propose and validate a novel statistical method for analyzing high-dimensional mediation effects in brain networks.

Main Methods:

• Development of a novel network mediation structural shrinkage (NMSS) prior for high-dimensional mediation analysis.
• Incorporation of brain structural connectivity network data as mediators.
• Application of the NMSS method to TOTXVI clinical trial data and simulation studies.

Main Results:

• The NMSS method accurately estimates high-dimensional coefficients and mediation effects, accounting for network properties.
• Simulation studies demonstrated the method's effectiveness and superiority over existing approaches.
• Analysis of TOTXVI data revealed significant mediation effects of brain connectivity on visual processing speed, influenced by IT intensity.

Conclusions:

• Brain connectivity plays a significant role in mediating neurocognitive deficits in pediatric ALL survivors.
• The proposed NMSS method provides a powerful tool for analyzing complex brain network data.
• Findings suggest potential for targeted interventions to mitigate neurocognitive impairments in survivors.