Table of Contents
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IMAGING
Histology | CT description |
---|---|
Juvenile pilocytic astrocytoma | "classic " cyst-with-mural nodule appearance. (ie. part of the cyst wall may not enhance) |
Low-grade astrocytoma | hypointense on pre-contrast T1 nonenhancing on post- T1 imaging |
Optic Glioma | isointense to the cortex (ie. hypointense to orbital fat) on T1 isointense to hyperintense to white matter and the cortex on T2 |
Meningioma | Isointense on pre-contrast T1 brightly enhancing on post-contrast T1 |
GBM | Mixed isointense on T1 ring enhancing on post-T1 |
PATHOLOGY AND HISTOLOGY
Pathologic Classification of Astrocytoma
Pilocytic astrocytoma (non-invasive, WHO grade I)
- hemispheric
- diencephalic
- optic
- brain stem
- cerebellar
Astrocytoma (WHO grade II)
- variants: protoplasmic, gemistocytic, fibrillary, mixed
Anaplastic (malignant) astrocytoma (WHO grade III)
- hemispheric
- diencephalic
- optic
- brain stem
- cerebellar
Glioblastoma multiforme (WHO grade IV)
- variants: giant cell glioblastoma, gliosarcoma
Astrocytes provide physical support to neurons and clean up debris within the brain.
oligodendrocytes are the myelin producing cells of the central nervous system
Microglia are the smallest of the glial cells. Some act as phagocytes cleaning up CNS debris.
Grading
Astrocytomas have great variation in their presentation. The World Health Organization acknowledges the following grading system for astrocytomas:
- Grade 1 — pilocytic astrocytoma - primarily pediatric tumor, with median age at diagnosis of 12
- Grade 2 — diffuse astrocytoma
- Grade 3 — anaplastic (malignant) astrocytoma
- Grade 4 — glioblastoma multiforme (most common)
Median Survival
Histology | Survival in Months |
---|---|
Low-grade Oligodendroglioma | 120 |
Low-grade Astrocytoma | 60 |
Anaplastic Oligodendroglioma | 60 |
Anaplastic Astrocytoma | 36 |
glioblastoma multiforme | 10 |
Histology | Median Survival yrs | Histology | Median Survival yrs |
---|---|---|---|
Pilo-A | 10+ | ||
Oligo-A | 7 | Oligodendorglioma | 10 |
Diff-A | 4.7 | ||
AA | 3 | anaplastic oligodendroglioma | 5 |
GBM | 1 |
A – Astrocytoma
AA – Anaplastic Astocytoma
RPA Classification
Class | Patient Characteristics | Median Survival (mo) |
---|---|---|
I, II | Anaplastic astrocytoma - Age <= 50, nl mental status - Age > 50, KPS > 70, symptoms > 3mo. |
40-60 |
III, IV | Anaplastic astrocytoma - Age <= 50, abnormal mental status - Age > 50, symptoms < 3mo. Glioblastoma - Age < 50 - Age > 50, KPS => 70 |
11-18 |
V, VI | Glioblastoma - Age > 50, KPS <70 or abnormal MS |
5-9 |
LOW GRADE GLIOMAS
General
- Astrocytomas: fibrillary, protoplastic, gemistocytic (transform into anaplastic form), pilocytic (young patients).
- 20-40 years old
- Typically in the cerebral hemisphere.
Mayo Experience: Surival of Low-Grade Supratentorial Gliomas
Survival | Pilo-A | Diff-A | OA | O |
Median (y) | — | 4.7 | 7.1 | 9.8 |
2 y (%) | 88 | 80 | 89 | 93 |
5 y(%) | 85 | 46 | 63 | 73 |
10 y (%) | 79 | 17 | 33 | 49 |
15 y(%) | 79 | 7 | 17 | 49 |
O, oligodendroglioma
OA, oligoastrocytoma
Malignant transformation
- 9% with RT vs 18% with surgery alone (Reichenthal)
Diagnosis
- Pilocytic Astrocytomas are enhancing lesions with cysts.
- The others are diffuse non-enhancing lesions that are poorly defined and are low signal on T1 and increased intensity on T2 images.
Surgery
- Diagnosis and removal of symptomatic area.
- Pilo-A is cured with complete resection if possible and with PR the survival is 80-90%. For other tumors, a CR results in survival of 80%
Radiation Dose and field
- 2 Randomized negative trials for dose escalation
- EORTC: 45 VS 59.4 58% VS 59% OS-5 NS
- NCCTG: 50.4 VS 64.8 73% VS 68% OS-5 NS
- Current dose: RTOG chose a 54 Gy dose to T2-weighted MR + 2 cm margin
Radiation Timing
- EORTC 22845 phase III 54 Gy adjuvant vs at progression: 55% vs 35% PFS-5 in favor of adjuvant RT but median survival time 7.4 was not affected.
- Observation is reasonable in adults with asymptomatic supratentorial low-grad glioma
Chemotherapy
- used to delay radiation; carboplatin and vincristine shows 3-yr PFS of 77% (Packer 1997).
Study
RTOG 9802 (Favorable Study) [1]
Patients
- Favorable patients (pts) (age <40 years [yrs] who undergo gross total resection [GTR])
Treatment
- observed postoperatively in a single arm Phase II study (Arm 1).
Results
- Arm 1, OS at 2- and 5-yrs is 99% and 94%. PFS at 2- and 5-yrs is 82% and 50%.
RTOG 9802 (Unfavorable Study) [1]
Patients
- Unfavorable pts (age ≥40 who have subtotal resection [STR] or biopsy [B])
Treatment
- randomized to either RT alone (54Gy in 30 fractions to a local treatment field) (Arm 2) or RT followed by 6 cycles of standard dose PCV (Arm 3).
Results
- Arms 2 (RT alone) and 3 (RT+PCV), there was no difference in OS or PFS. OS at 2- and 5-yrs was 87% and 61% with RT alone versus (vs) 86% and 70% with RT+PCV (p=0.72).
TECTAL GLIOMA
THALAMIC GLIOMA
- Thalamic and brain stem tumors constitute 10-15% of primary intracranial gliomas of childhood, with a dominant age being 4-14 years.
- Adult thalamic and brain stem tumors constitute 35% of intracranial gliomas
- Due to their critical location, thalamic tumors often require treatment without biopsy confirmation. However, autopsy results and more recently stereotactic biopsy have revealed that the majority of the tumors are glial neoplasms
- Total surgical resections are generally less feasible because of the resulting neurological deficits.
- Treatment is as per pathology
OPTIC PATH GLIOMA
- Epidemiology
- 5% of pediatric brain tumors
- nearly all are found in patients younger than 20 years of age and mostly 10 years of age.
- 20-40% associated with NF-1
- 5-10% of patient with NF-1 have optic path glioma
- patients with NF-1 have more indolent course
- Presentation
- loss of visual acuity 70%, strabismus and nystagmus 33%, visual field impariment 8%
- developmental delay, macrocephaly, ataxia, hemiparesis, proptosis, and precocious puberty
- upto 30% of children with optic chiasm (73% of cases) involvement initially present with precocious puberty.
- NF-1 patients have anterior > posterior visual pathways involved.
- Gliomas along te anterior visual pathway occurred in 15% of NF-1 patients and were occasionally bilateral.
- Biopsy not needed
- Treatment
- Carboplatin and vincristine to delay radiation in pre-pubertal patients
- 3 years progression free survival rate of 77%
- 50-54 Gy in 150 to 180 cGy per fraction
- 45 Gy at 1.5 Gy per fraction for < 3 year-old.
OLIGODENDRIOGLIOMAS
General
- 20-50 years
- Loss of 1p and 19q
- 80% are in the white matter
- Typically presents with seizures
- From oligodendrocytes which mylelinate the neurons.
Pathology
- Small round cells with perinuclear halo and can see calcifications.
- Grade: either low (5 year survival of 75%) or anaplastic OG (45%).
- If have astrocytomas + ependymomas elements then called a mixed OG with survival of 65%.
- If recurs then GBM or anaplastic astrocytoma.
Diagnosis
- CT or MRI scan shows an enhancing lesion with hemorrhage or necrotic area.
- MR specttroscopy shows
- reduction in N-acetyle asparate (NAA) signal
- increase in choline peak
Treatment
- Surgery: goal is CR
- Radiotherapy: Added if PR or if intact with 54 for LG and 60 for the anaplastic tumors.
- Chemotherapy: PCV is useful in this group of patients especially 1p 19q deletions