Treatment Paradigm Flashcards
What is the management paradigm for standard-risk MB?
COG approach: Standard-risk MB management: max safe resection → RT with concurrent weekly vincristine → adj chemo (eight 6-wk cycles of cisplatin/CCNU/vincristine). RT is CSI to 23.4 Gy → cone down 1 (CD1) to PF to 36 Gy, then cone down 2 (CD2) to cavity/residual or PF to 54–55.8 Gy; or CSI to 23.4 Gy → CD to cavity/residual to 54–55.8 Gy (MDACC).
What chemo regimens are typically used for MB?
Initial studies that established the efficacy of reduced-dose CSI (23.4 Gy) with chemo in standard-risk MB used concurrent vincristine with RT → adj cisplatin/CCNU/vincristine. The CCG A9961 trial recently found similar outcomes when cyclophosphamide was substituted for CCNU. (Packer R et al., JCO 2006)
What is the management paradigm for high-risk MB?
High-risk MB management paradigm for pts >3 yo: same as standard risk, but the CSI dose is 36 Gy; also, nodular intracranial or spinal mets may to be boosted to 45–50.4 Gy depending on location (whether lesion is above or below SC terminus).
For high-risk MB pts, what is the total boost dose for pts with intracranial (M2) vs. spinal (M3) mets?
Per COG ACNS0332, boost intracranial mets to 50.4 Gy, focal spinal mets below the cord terminus to 50.4 Gy, focal spinal mets above the cord terminus to 45 Gy, and diffuse spinal Dz to 39.6 Gy.
Estimate the 5-yr EFS for standard- and high-risk MB.
The 5-yr EFS for standard risk is 80% and for high risk is 50%–60%.
What is the management paradigm for MB pts <3 yo?
MB pts <3 yo management paradigm: max safe resection → chemo until pt reaches 3 yo. At 3 yo, consider standard therapy with CSI → more chemo. If desmoplastic histology, consider omitting RT altogether. New protocols use surgical bed RT alone after induction chemo in 18- to 36-mo pts.
What are the potential risks of aggressive Sg in the PF?
The major risk of aggressive Sg in the PF is PF syndrome (10%–15% of cases): mutism, ataxia, dysphagia, hypotonia, respiratory failure, and mood lability caused by disruption of the dentatorubrothalamic pathway to the supplemental motor cortex. PF syndrome typically presents 12–24 hrs postop and improves over several mos. Other potential complications include aseptic meningitis and CSF leakage. Do not delay RT b/c of PF syndrome.
