Staging Disease for Adjuvant Treatment
Postoperative treatment algorithms are affected by stratification of patients into high-risk and average-risk groups, as defined below (17).
- Older: Age >3 years.
- Focal disease: No leptomeningeal seeding (ventricular spinal, or subarachnoid) on MRI. Negative CSF cytology (obtained > 10 days postoperatively). No extraneural metastasis (i.e., bone, lungs).
- Good resection: < 1.5 cm2 of residual tumor on postoperative MRI.
- Young: Age < 3 years.
- Disease spread: Evidence of spread through CSF space or metastasis to extraneural sites.
- Significant residual disease: Residual disease > 3 cm3.
- 2340–3600 cGy with boost: All patients who are at least 3 years of age should receive postoperative external beam radiation therapy (range, 2340–3600 cGy of craniospinal radiation) with a boost to the posterior fossa (typically to approximately 5400 cGy) (2, 7, 21, 26).
- Reduced dose: A reduction in the dose of radiation therapy can be considered in average-risk patients.
- Younger than 3 years: Reduced-dose radiation therapy or no radiation therapy can be considered in patients less than 3 years of age.