Gliomas High Grade

General

  • 35-45% of all brain tumors
  • Greater than 40 years old
  • p53 mutation
  • Most are in the cerebral aspect of the brain
  • Prognostic Factors: age, KPS, histology, neurological status.

Pathology

  • Astrocytomas arise from astrocytes/support cells, which contain GFAP.
  • Grading: low, intermediate (the anaplastic astrocytomas with hypercellularity and pleomorphic nuclei) and the high grade (GBM with necrosis).
  • Labeling indices include the Brdu and Ki67

Presentation

  • HA< Seizure, mass effect, HA
  • Spread locally and rarely to distant sites

Diagnosis

  • The T2 MRI scan shows a larger tumor.
  • The non-contrast CT scan shows a hypodense lesion.
  • Biopsy of the lesion.

Treatment

Surgery

  • diagnosis or partial resection to decompress or to attempt removal of a small lesion. Resection alone is not curative.

Chemotherapy

  • Phase III EORTC and NIC-C (Stupp) in GBM: temozolomide (75 mg/m2/d for 7 days) given during conventional fractionated radiotherapy, followed by six cycles of standard-dose temozolomide (200 mg/m2/d for 5 days every 28 days) after radiotherapy. 26% vs 10% P <0.0001 2-yr survival advantage. Temodar is being studied in AA.

Radiotherapy

  • The main mode of treatment to doses of 60Gy/30 fractions with 2cm margin on the T2 weighted images and reduction after 45Gy to 1.5cm on T1 weighted images. Treat the edema because can have tumor infiltration.
  • BTSG 6901 and 7201 have shown superior survival of RT + surgery over chemotherapy alone or surgery alone.
  • BTSG 6601 reported that doses of 60Gy were needed and BTSG 8001 showed that a cone down was possible.
  • RTOG 7401 showed no benefit for a boost above 60Gy.
  • The BTCG (66Gy) and RTOG 9006 (72Gy) showed no benefit in BID to over daily fractionation.

Anaplastic Oligodendrogliomas

  • PCV chemotherapy in 1p19q anaplastic oligodendrogliomas: RTOG induction PCVx4 + RT vs RT alone with salvage chemotherapy showed 2.6 yr vs 1.9 yr PFS in induction arm (no OS advantage). Survival was especially good for the 1p19q patients in the trials.

Brain Stem Glioma

  • Institutional studies from CCG and UTSF showed improvement with hyperfractionation in children but randomized trial was negative.
  • GTV is T2-weighted target
  • CTV is GTV + 1.5 cm
  • PTV should be covered by 100% isodose line to 55.8 Gy
  • Dose homogeneity in 2D treatment should be within +10% and –5% of the target dose (5580 cGy).
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