Intraoperatively Observed Site of Origin and Growth Pattern of Medulloblastoma

An International Multicenter Prospective Cohort Study Investigating the Intraoperatively Observed Site of Origin and Growth Pattern of the Molecular Groups of Medulloblastoma

The goal of this observational study is to provide accurate and systematic data on the site of origin and growth pattern of medulloblastoma from a neurosurgical perspective. By integrating intraoperative, radiological and genetic classification data, this study will contribute to our current understanding of the development, site of origin and growth pattern of medulloblastoma and advance the predictive accuracy of radiogenomics models. Patients with histologically confirmed medulloblastoma who undergo surgical resection at a high-volume center with expertise in pediatric neurosurgery will be included.

The main questions it aims to answer are:

• Is there a significant difference between the intraoperatively observed site of origin and the preoperatively or postoperatively radiologically assessed site of origin of medulloblastoma?
• How does the intraoperatively observed site of origin align with the site of origin associated with the molecular group based on the developmental cell lineage concept of medulloblastoma?
• Does incorporating the intraoperatively observed site of origin as a feature improve the predictive accuracy of radiomic models for molecular group classification?

Participants will:

• Undergo intraoperative assessment of site of origin and growth pattern by an experienced pediatric neurosurgeon.
• Have their site of origin and growth pattern evaluated on pre- and postoperative magnetic resonance imaging by an neuroradiologist with expertise in pediatric brain tumors.

Inclusion Criteria:

• Patients who are referred for surgical resection of a medulloblastoma at a hospital with expertise in pediatric neurooncology
• Both pediatric patients (aged < 18 years at the time of diagnosis) and adult patients (aged > 18 years at the time of diagnosis)

Exclusion Criteria:

• Patients who are preoperatively admitted with severe tumor hemorrhage accompanied by clinical deterioration are excluded because these patients frequently do not receive magnetic resonance imaging as would be necessary for the present study, and the intraoperative assessment of the STO is limited in accuracy due to decreased visibility caused by the intra- and extratumoral hemorrhage.
• If an intraoperative complication occurs (e.g. bleeding) which impairs visibility of the neuroanatomic structures and does not allow an accurate assessment of the STO, the patient is excluded.
• If the histopathological and molecular analysis does not confirm the diagnosis of a MB, the patient has to be excluded as well.