Gliomas / Glioblastoma Multiforme (GBM)

FACTS

  • GBM can be primary or a transformation of diffuse infiltrating astrocytoma (Grade 2/3)
    • primary: EGFR mutation; elderly usually primary
    • secondary: TP53 mutations
  • mechanisms of spread: subarachnoid seeding (via CSF), white matter
How gliomas spread through white matter
Spread through…
Leads to involvement in …
peduncles
brainstem
genu / body of corpus callosum
bilateral frontal lobes (”butterfly glioma”)
splenium of corpus callosum
parietal / occipital lobes
notion image
 
 
  • How gliomas spread via white matter
Spread through…
Leads to involvement in …
peduncles
brainstem
genu / body of corpus callosum
frontal lobes
splenium of corpus callosum
parietal / occipital lobes
 

HPI

universal ROS
  • KPS

PHYSICAL EXAM

universal exam
  • Visual fields / acuity
  • speech (naming, repetition)

IMAGING

MR spectroscopy:
  • NAA/Creatine peaks DECREASED as grade INCREASES
  • Choline peak INCREASED
    • NOTE: [11c] choline has high diagnostic accuracy in detecting relapse from radiation induced necrosis
MRI without contrast:
  • HGG are DWI restricting (unlike LGG)
A/P
  • First line treatment: Stupp Protocol
    • Maximal safe excision
    • Concurrent TMZ (temozolomide) + XRT (60 Gy over 30 sessions: 5d x 6 wks)
  • counsel: prognosis depends a lot on KPS, grade, neurologic deficit, histology, EOR, genetics (IDH, MGMT)
    • IDH mutation is good
    • MGMT mutation is good
  • Recurrences vs. pseudoprogression (Treatment effect, radiation necrosis)
    • Order MRI spectroscopy to help distinguish
    • Tx for pseudoprogression:
      • steroids
      • bevacazumab (Avastin)
      • LITT
      • ?hyper-baric O2

Temozolomide

  • MOA: alkalating agent → deposits methyl on DNA → cytotoxic lesions → cell death
    • MGMT removes these lesions, hence it’s better to have an MGMT mutation