Primary Intracranial Neoplasms Flashcards
CNS Anatomy:
What meningeal layers are also known collectively as the leptomeninges?
arachnoid mater and pia mater
CNS Anatomy:
What meningeal layer is also known as the pachymeninges?
dura mater
CNS Anatomy:
What dural fold separates the cerebral hemispheres?
How about the cerebrum from the brainstem and cerebellum?
falx cerebri
falx or tentorium cerebelli
CNS Anatomy
The central sulcus is found in between what lobes of the cerebrum?
frontal and parietal
CNS Anatomy
The sylvian fissure is found in between what lobes of the cerebrum?
frontal and temporal
CNS Anatomy
The calcarine sulcus is found in between what lobes of the cerebrum?
parietal and occipital
CNS Anatomy
What is the narrowest canal of the intracranial nervous system and is therefore the most common location of obstruction of flow by compression or tumor deposits, resulting in noncommunicating (obstructive) hydrocephalus?
Slyvian aqueduct
CNS Epidemiology
What extrinsic factor is mostly associated with an increased risk of primary brain tumor?
prior radiation exposure
CNS Epidemiology
Enumerate hereditary diseases associated with the development of intracranial malignancy.
NF1 and 2
vHL
tuberous sclerosis
others (rb and LFs)
CNS
2D RT
What is the plane connecting points in the two external
auditory meatus and one anterior infraorbital edge?
Frankfort horizontal plane
CNS
2D RT
What is the location of the hypothalamic structures in relation to the sella (lateral radiograph)?
1 cm superior to the sellar floor
CNS
2D RT
What is the location of the optic canal in relation to the hypothalamus (lateral radiograph)
1 cm superior and 1 cm anterior to the hypothalamus
CNS
2D RT
What is the location of the pineal body (tentorial notch) in relation to the EAM? (lateral radiograph)
1 cm posterior and 3 cm superior to the EAM.
CNS
SRS
What is the maximum tolerated dose of a single fraction SRS for tumors ≤20, 21 to 30, and 31 to 40 mm in maximum diameter, respectively, as established by the RTOG 90-05?
24 (<20 mm)
18 (21 to 30 mm)
15 (31 to 40 mm)
CNS
Brachytherapy
What is the radioactive material used in brachytherapy of CNS tumors?
125-I
CNS
Chemotherapy and targeted agents
What is the only agent to demonstrate a survival benefit for glioblastoma and anaplastic astrocytoma patients in randomized clinical trials.
TMZ
CNS
Chemotherapy and targeted agents
What is the only approved targeted agent for use in GBM?
Bevacizumab (Avastin)
CNS
Malignant or high-grade gliomas account for approximately half of all primary brain tumors in adults.
TRUE or FALSE?
True
CNS
_________ accounts for approximately 75% of all high-grade gliomas.
GBM (WHO Grade IV)
CNS
What are the histopathologic features of GBM? Any three of which suffice to make the diagnosis.
nuclear atypia
mitotic activity
vascular proliferation
necrosis,
(MaNaVPN)
CNS
What is the typical picture of GBM in MRI?
vasogenic edema and ring enhancement around central necrotic regions
CNS
GBM
What is the most important and second most significant predictor of survival/prognostic factor?
Age (≤50)
KPS ≥70
Curran et al. used nonparametric recursive partitioning analysis (RPA) (a
statistical tool that allows for the identification of significant prognostic factors
and subsequent classification of patients into groups with similar outcomes) to
analyze data from three RTOG trials that included 1,578 patients with malignant
gliomas.
CNS
GBM
What is the standard management?
maximal safe resection
+ RT with concurrent TMZ (75 mg/m2)
+ 6 cycles of adjuvant TMZ (5/28 day schedule)
CNS
GBM
Based on earlier studies
78% and 56% of recurrence occur within __cm and __cm from the enhancing tumor on CT respectively.
78% within 2 cm
56% within 1 cm
CNS
GBM
What dose prescription is considered the “standard approach”?
59.4 to 60 Gy / 1.8-2 / 30-33
CNS
GBM
If unimodality therapy is being contemplated, what is the treatment consideration for MGMT-unmethylated GBM?
RT alone
CNS
GBM
If unimodality therapy is being contemplated, what is the treatment consideration for MGMT-methylated GBM?
TMZ
CNS
GBM
Although it confers no survival benefit for newly diagnosed glioblastoma,
this agent can be an effective salvage therapy at time of progression, although there
are no categorical data demonstrating that it prolongs survival in patients with
recurrent GBM.
It can also be useful in large tumors with significant cerebral
edema by improving neurologic disability and sparing prolonged steroids.
What is this agent?
Bevacizumab
CNS
Glioma
What is the difference in the histologic features of GBM and WHO grade III gliomas?
no necrosis and no neovascularization.
CNS
Glioma
What factors best define the prognosis in patients with anaplastic gliomas?
Molecular factors (1p 19q deletion and IDH1 mutation)
CNS
Glioma
Molecular factors like IDH1 mutation and 1p19q codeletions confer some chemosensitivity benefit for anaplastic gliomas.
What is the most common drug regimen used for these types of gliomas?
PCV
Procarbazine
CCNU (lomustine)
vincristine
CNS
Anaplastic astrocytoma
What is the optimal timing for PCV, RT, and TMZ if all three approaches are to be used?
doesn’t matter
Based on the NOA-04 trial, if all three
approaches, i.e., radiation, temozolomide, and PCV are to be used, sequencing
may not matter.
CNS
What chromosomal/gene abnormality is observed in 60% to 80% of pilocytic astrocytoma?
tandem duplication of chromosome 7q34 resulting in fusion of the BRAF and KIAA1549
CNS
What is the role of RT in LGG treatment?
for tumors that have recurred more than once, or for those with considerable residual disease in a critical location, where even slight progression could result in significant morbidity
CNS
What is the standard of care RT dose for patients with LGGs?
50 to 54 Gy in 1.8 Gy fractions, is the standard of care for patients with LGGs.
CNS
Identify:
______________ is a narrowly defined but phenotypically and molecularly distinct tumor that is characterized by K27M mutations in the histone H3 gene HeF3A, or less commonly in the related HIST1H3B gene, occurring primarily in children (but sometimes in adults), with a diffuse growth pattern and midline location (e.g., thalamus, brainstem, and spinal cord).
Diffuse midline glioma
CNS
This entity which was described as a diffuse involvement of more than 2 lobes of the brain was removed from the 2016 WHO classification and is now considered a pattern of spread, therefore, the lack of data recommends treating by histologic and molecular factors.
Gliomatosis cerebri.
CNS
What is the pathologic hallmark of ependymoma?
Rosette formation
CNS
Where is the most common location of adult ependymoma?
Spinal canal
CNS
What is the standard of care for adult ependymomas?
PORT
typically 54 to 59.4 Gy
CNS
For PF ependymoma, what is the tumor volume?
GTV or tumor bed + 1-2 cm margin.
Entire PF irradiation is not necessary
-Paulino
CNS
For ependymoma, when do you do CSI?
and what is the exception?
For patients with neuraxis spread (MR and cytology positive)
except WHO Grade I, myxopapillary ependymoma where MR evidence of neuraxis spread can be focally treated with RT.
CNS
What are these clustered cells surrounding a central eosinophilic core are characteristic of medulloblastoma?
Homer wright rosettes
CNS
What is the recommended CSI dose for patients with average-risk medulloblastoma?
23.4 Gy CSI with boost to the tumor bed with 1.5 cm margin.
CNS
What is the recommended volume of boost for patients with high-risk medulloblastoma?
entire posterior fossa to 54 Gy rather than tumor bed boost
CSI is full-dose at 36 Gy
CNS
Why are corticosteroids usually held at presentation unless absolutely necessary (e.g., impending brain herniation)?
Corticosteroids should be held at presentation unless absolutely necessary (e.g., impending brain herniation) because their “lytic” effect on lymphoma may lead to a false-negative biopsy.
CNS
What is the chemotherapeutic agent proven to improve survival compared to RT alone in patients with PCNSL?
Methotrexate
CNS
What is the standard total dose range for WBRT in PCNSL?
45 to 50 Gy
CNS
What is the reduced WBRT dose for WBRT in PCNSL who responded completely with R-MVP?
23.4 Gy
CNS
What histologies are classified as WHO Grade II meningioma?
Clear Cell
Chordoid
CNS
What histologies are classified as WHO Grade III meningioma?
Rhabdoid
Papillary
CNS
What condition predisposes a person to develop multiple meningiomas?
NF2
CNS
Main risk factor for the development of meningioma (aside from genetics)
Ionizing radiation exposure
CNS
What is the typical RT prescription for PORT in grade I meningiomas?
50 to 54/1.8 to 2
CNS
What is the typical RT prescription for PORT in atypical meningiomas?
54 to 59.4 in 30 to 33 fx
CNS
What is the typical RT prescription for PORT in malignant meningiomas?
59.4/33
CNS
What is the typical RT prescription for cranipopharyngiomas?
50.4 to 54 Gy in 28 to 30 fractions (1.8 Gy)
CNS
What is the typical RT dose for vestibular schwannoma?
50 to 55 Gy in 25-30 fractions
CNS
What is the standard treatment for vestibular schwannoma?
Microsurgery
CNS
What is the most common cerebellar tumor in adults?
Hemangioblastoma
