2. The central nervous system (CNS) is enveloped by three meningeal layers: the dura
mater (also known as the pachymeninges), the arachnoid mater, and the pia mater.
(leptomeninges)
Dural folds separate the two hemispheres of the cerebrum (falx cerebri) and the
cerebrum from the cerebellum and brainstem (tentorium or falx cerebelli).
5. INCIDENCE
• Second commonest form of cancer in children
• Accounts for 3.5% of all deaths in the 1-14 year age group
• Sixth commonest cause of cancer deaths in adults
• 25% of all tumors in adults are in the brain and 35% are
and 40% are metastatic
Age
Adults- Supratentorial: 80-85%
Intratentorial: 15-20%
Children-Intratentorial: 60%
Supratentorial: 40%
6. ~ Most primary tumors are sporadic and of unknown aetiology
~ Secondary tumors vary greatly between 14-40%
~ Fewer than 5% are associated with hereditary syndromes that predispose to
neoplasia
Prior exposure to ionizing radiation is a known risk factor for development of primary
CNS tumors, particularly meningiomas, but also gliomas, sarcomas, and other tumor
types.There is a 2.3% incidence of primary brain tumors in children treated with
prophylactic cranial irradiation for acute leukemia, a 22- fold increase over expected.
7. Syndrome Gene locus Gene Type of CNS tumour
NF type 1 17q11 NF1 Neurofibromameningioma,
optic nerve glioma
NF2 22q12 NF2 Meningioma, schwannoma
TS 9q34,16p13 TSc1/TSC2 SEGA
VHL 3p35 VHL Haemangioblastoma
Li-Fraumani 17q13 p53 glioma
Gorlin’s
syndrome
9q31 PNET
Heritable syndromes with increased risk of CNS tumours
8. Classification of Tumors of the Central Nervous System: Based on the World Health
Organization Classification
11. Extra-axial Supratentorial
• Choroid plexus papilloma/carcinoma
• Langerhans cell histiocytosis
• Epidermoid/Dermoid
• Arachnoid cyst
Metastasis
Up to half of metastatic brain tumors are from lung cancer.
Other type of cancer that commonly spread to brain include
Melanoma
Breast cancer
Colorectal cancer
Kidney cancer
Nasopharyngeal cancer
Cancer of unknown primary site
21. SITE SYMPTOMS
PRIMARY MOTOR CORTEX Lesions: ↑/↓ tone; ↓ power; ↓ fine motor
function on contra lateral side
PRE MOTOR CORTEX moderate weakness in proximal
muscles on contralateral side
SUPPLEMENTARY MOTOR CORTEX mutism, akinesis; speech returns but it
is non-spontaneous
FRONTAL EYE FIELDS eyes deviate ipsilaterally with
destructive lesion and contralaterally
with irritating lesions
BROCA’S SPEECH AREA motor aphasia
22. SITE SYMPTOMS
ORBITAL PREFRONTAL
CORTEX
Disinhibited, impulsive
behaviour
(pseudopsychopathic)
Inappropriate jocular
affect, euphoria
emotional lability, Poor
judgment and insight,
Distractibility
DORSOMEDIAL
PREFRONTAL CORTEX
Paucity of spontaneous
movement and gesture,
Sparse verbal output
(repetition may be
preserved), Lower
extremity weakness and
loss of sensation,
Incontinence
DORSOLATERAL
PREFRONTAL CORTEX
executive function
deficit; disinterest /
emotional reactivity;
attention to relevant
23.
24.
25. PARIETAL LOBE
•Anterior zones - process somatic sensations and
perceptions
•Posterior zones - integrate information from vision with
somatosensory information for movement
•Spatial Map in the Brain
26.
27. Anatomy of the Temporal Lobe
• Tissue below the Sylvain Fissure and anterior to the occipital cortex
Subcortical Temporal Lobe Structures
– Limbic cortex
– Amygdala
– Hippocampal Formation
Temporal cortex-
• Lateral surface – Auditory areas
• Brodmann’s areas 41,42, and 22
– Ventral Stream of Visual Information -
• Inferotemporal cortex
• Brodmann’s areas 20, 21,37, and 38
Insula(gustatory cortex/auditory association area
Multimodal Cortex or Polymodal Cortex
30. BASAL GANGLIA
• In general, symptoms vary and may include:
• Movement changes, such as involuntary or slowed
movements
• Increased muscle tone
• Muscle spasms and muscle rigidity
• Problems finding words
• Tremor
• Uncontrollable, repeated movements, speech, or cries
(tics)
• Walking difficulty
31. THALAMIC AND HYPOTHALAMIC TUMORS
• Symptoms of hormone imbalance, including weight
loss/gain
• Symptoms of salt and water imbalance, including
retaining water, swelling and frequent urination
• Changes in vision (since the thalamus and hypothalamus
are found close to the visual pathway system in the brain)
32. CORPUS CALLOSUM
A tumor here can result in
disconnection/split brain syndrome
It may cause word blindness and
difficulty to carry out intended
action and movements(Bristow’s
syndrome)
33. The initial workup of patients with brain tumors must include a complete history
and physical examination.
Imaging Studies
MRI with a gadolinium-containing contrast agent is the imaging modality of choice
for most CNS tumors. Computed tomography (CT) is generally reserved for those
situations in which MRI is contraindicated, such as implanted pacemaker, metal
fragment, or paramagnetic surgical clips, or where there is a need to image the
extent of calcification or hemorrhage.
DIAGNOSTIC WORKUP
34. Magnetic Resonance Imaging
• The most useful imaging studies are T1-weighted sagittal images, gadolinium (Gd)-enhanced and
unenhanced T1 axial images, T2-weighted axial images, and fluid-attenuated inversion recovery (FLAIR)
sequences.
• As is the case with CT contrast agents, gadolinium-based contrast leaks into parenchyma in areas with
BBB breakdown, and the paramagnetic properties of gadolinium generate hyperintense signal on T1
scans.
• T1 images usually are better at demonstrating anatomy and areas of contrast enhancement.
• T2 and FLAIR images are more sensitive for detecting edema and infiltrative tumor.
• Tumor appearance on T1-weighted MRI is similar to that on CT, although tumor volumes are better
delineated on MRI, particularly with low-grade neoplasms that do not demonstrate contrast enhancement
• With the increasing incidence of posttreatment “pseudoprogression,” additional specialized diffusion,
perfusion, and spectroscopic sequences are being increasingly used to distinguish tumor from necrosis or
pseudoprogression, and positron emission tomography (PET) imaging may also have some role in
fluorodeoxyglucose-PET, fluorothymidine, and F-DOPA PET imaging is being evaluated. Diffusion-weighted
and functional MR also has utility in guiding resection, and in this context, magnetoencephalography is
35. Neuraxis Imaging
• For neoplasms with high risk of CSF spread, staging of the neuraxis is essential. Gd-enhanced MRI of the
spine is the imaging modality of choice.
Histologic Confirmation of Diagnosis
• The morbidity of biopsy has decreased significantly with improvements in operative technique and
anesthesia, as well as with the availability of stereotactic biopsy techniques.
• Exception might be made in selected patients, such as those patients with known active systemic cancer
and multiple lesions that are radiographically consistent with brain metastases, patients with typical clinical
and MRI findings of a brainstem glioma or optic nerve meningioma, HIV-positive patients with CT or MRI
findings consistent with primary CNS lymphoma and positive Epstein-Barr virus polymerase chain reaction in
the CSF, or patients with secretory germ-cell tumors.
36. Stereotactic biopsy : When imaging tests show there may
be a tumor deep in the brain in a hard to reach place, a
stereotactic brain biopsy may be done. This kind of biopsy
uses a computer and a 3-dimensional (3-D) scanning
device to find the tumor and guide the needle used to
remove the tissue. A small incision is made in the scalp
and a small hole is drilled through the skull. A biopsy
needle is inserted through the hole to remove cells or
tissues so they can be viewed under a microscope by a
pathologist to check for signs of cancer.
Open biopsy : When imaging tests show that there may
be a tumor that can be removed by surgery, an open
biopsy may be done. A part of the skull is removed in an
operation called a craniotomy. A sample of brain tissue is
removed and viewed under a microscope by a
pathologist. If cancer cells are found, some or all of the
tumor may be removed during the same surgery. Tests
are done before surgery to find the areas around the
tumor that are important for normal brain function.
37. Cerebrospinal Fluid Cytology
• CSF cytology is essential for staging tumors with a propensity for CSF spread (e.g.,
medulloblastoma, PNET, germ cell tumors, CNS lymphoma).
• Sampling of the CSF in the immediate postoperative period may lead to false-positive results,
however, and is best done before surgery or more than 3 weeks after surgery, as long as
intracranial pressure is not elevated.
• CSF spread of tumor may be associated with several abnormal CSF findings. These include CSF
pressure >150 mm H2O at the lumbar level in a laterally positioned patient, elevated protein level
(>40 mg/dL in the lumbar cistern), a reduced glucose level (<50 mg/mL), and the finding of tumor
cells by cytologic examination.
• Tumor markers in the CSF may help in making the diagnosis.
38. GENERAL MANAGEMENT
The medical management of patients with brain tumors includes management of increased intracranial
pressure, seizures, and venous thromboembolic disease.
Cerebral Edema
• Glucocorticoids are used to control neurologic signs and symptoms caused by cerebral edema.
• Lower doses of steroids (e.g., 2 to 4 mg dexamethasone) twice daily have been shown to be as effective as
higher doses.
• Prolonged steroid use is associated with multiple medical problems, and therefore steroids should be
discontinued or tapered to the lowest dose necessary, as soon as possible.
• Dexamethasone is the most common corticosteroid used for historical reasons and because of minimal
mineral-corticoid effects.
• As with all corticosteroids, a slow taper is necessary to prevent a rebound in cerebral edema and also to
allow the pituitary–adrenal axis to recover.
39. Seizures
• Patients with seizures require anticonvulsants. Because anticonvulsants such as carbamazepine,
phenobarbital, and phenytoin induce hepatic cytochrome P450 isozymes, which increase the
metabolism and clearance of several cancer chemotherapy agents such as paclitaxel and
irinotecan, non–enzyme- inducing anticonvulsants, such as levetiracetam, lacosamide, lamotrigine,
and pregabalin are preferred.
• Prophylactic anticonvulsant use (in patients who have never experienced a seizure) remains
controversial, although practice guidelines from the American Academy of Neurology
recommended against their use because of lack of data.
40. SURGERY
Surgical procedures can be summarized as
biopsy for diagnosis only, resection for cure,
surgical debulking for management of mass
effect–related symptoms, CSF diversion
procedures to relieve acute symptoms caused
by increased intracranial pressure or
hydrocephalus, and, increasingly, re-resection
to distinguish and manage the effects of
progressive tumor from symptomatic necrosis
or pseudoprogression
41. Other roles of surgery include the
placement of chemotherapy wafers,
brachytherapy devices, and catheters for
interstitial drug delivery and for
monitoring tumor drug concentrations.
Complete resection of tumor is
associated with a survival advantage for
some tumor types.
However, for some radiosensitive and/or
chemosensitive malignancies such as
primary CNS lymphoma, aggressive
resection is unnecessary, and the
surgeon’s role is limited to providing
diagnostic material.
42. RADIOTHERAPY
Radiobiologic Considerations Underlying Tissue Injury
• The process of radiation injury in the brain is highly complex and dependent on a variety of
technical factors, including dose, volume, fraction size, and the specific target cell population, as
well as secondary mechanisms of expression of injury such as vascular leak causing edema,
vascular endothelial loss resulting in hypoxic injury, reactive gliosis, and to-date inadequately
studied host factors.
• Some structures (e.g., optic chiasm, hypothalamus, lacrimal gland, lenses, etc.) appear to be
substantially more sensitive to radiation than others.
• The effect on endothelial cells often becomes manifest as an early T2 signal abnormality on MRI,
possibly due to disruption of the BBB and edema formation. Metabolic perturbations observed
with PET may reflect oligodendroglial demyelination. Further vascular perturbation and
regeneration in response to injury results in an enhancing lesion on imaging. Delayed effects
include white matter necrosis and vascular obliteration.
43. Anatomic Landmarks
With conventional simulation, radiographic and surface topographic reference points for
appreciation of beam-to-head projection geometry are necessary. The external auditory meatii
define anatomic reference planes such as Reid’s baseline and the Frankfort horizontal plane,
connecting points in the two external auditory meatii and one anterior infraorbital edge.
Treatment Setup
The head should be positioned so that its
major axes are parallel with and
perpendicular to the central axis incident
beam and the treatment table. It may be
preferable to fully flex or extend the neck in
some patients, depending on tumor
location and choice of beams
Reproducibility of head positioning is
achieved by using a fixation device.
44. RadiotherapyTechniques
The most commonly employed radiotherapy techniques in the management of CNS tumors are partial- brain
irradiation, whole-brain radiotherapy (WBRT), craniospinal irradiation (CSI), stereotactic radiosurgery (SRS),
fractionated stereotactic radiotherapy (FSRT), and, less commonly, brachytherapy.
Whole-Brain Radiotherapy
WBRT is used most often for patients with brain metastases but also for patients with primary CNS
lymphomas and glioblastomatosis cerebrii and as a component of CSI.
Whole-brain irradiation is administered through parallel-opposed lateral portals.The inferior field border
should be inferior to the cribriform plate, the middle cranial fossa, and the foramen magnum, all of which
should be distinguishable on simulation or portal localization radiographs.
The two general approaches of treatment planning are 2D and 3D. Two dimensional planning involves the use
of beams that are coplaner that is oriented in same plane. 3D planning uses beams that are non coplaner that
is oriented in different planes.
Advantage of 3D planning is that essentially number of beam trajectories permitting greater sparing of critical
normal tissue and allowing higher tumor dose to GTV and CTV.
45.
46. A. Axial MRI Scan with contrast of a right
pilocytic astrocytoma.
B. showing GTV and CTV
47.
48. Craniospinal Irradiation
Traditional CSI techniques use opposed lateral cranial fields and one or more posterior spinal fields, depending on
patient size.The volume of irradiation includes- Entire brain and its meningeal coverings with the CSF, Spinal cord
and the leptomeninges with CSF, Lower border of the thecal sac, Posterior fossa – boost.
The junctioning of noncoplanar fields in the cervical region is potentially hazardous because of the risk of overlap
resulting in radiation myelitis.
Patients are simulated prone, with vacuum bags under the abdomen and knee support.The head is supported on a
headrest with jaw and forehead support to allow for respiration, the head is extended comfortably to prevent the
spine field from exiting through the jaw.The head is then immobilised in a thermoplastic mask.
It is desirable to obtain as straight a spine as comfortable to standardise the distance of the spinal cord (or column in
children under 18) from the beam source.
Treatment is with a two phase technique; children under 15 are treated with 23.4 Gy to the craniospinal axis and a
30.6 Gy boost to the primary tumour with a 2 cm expansion. Older children and adults receive 36 Gy to the
craniospinal axis with an 18 Gy boost to the tumour bed.
49. The superior spinal field is placed first. It should be aligned so that central beam axis is perpendicular to the
vertebral column, and the field should be as large as possible.The superior beam edge should exit below the level
of the jaw to prevent oral early and late effects.The lateral edges should be 1 cm to the pedicles of the spine to
ensure adequate dose within the meninges.The inferior extent of the field should include the filum terminal, as
visible on the MRI, or alternatively be junctioned with an inferior spinal field.
The inferior spinal field should be matched at the level of the mid cord, and the junction feathered by 1 cm every
day to reduce the impact of hot and cold spots.
Cranial Fields
The cranial fields are placed next.These fields should have the collimator rotated to match the divergence of the
posterior spine field.
Junction:The junction with the spine field can be performed through several means. A single match rotates the
collimator only, with hot and cold spots located at the junction.This technique necessitates a feathered junction
to blur out this region.A double match rotates the collimator and the couch to align the divergence of the lateral
beams with the divergence of the spinal field.
Phase two involves a boost to the primary tumour bed and any metastatic sites to 54 Gy.
50. Stereotactic Radiosurgery
Stereotactic radiosurgery requires a team
comprised at a minimum of a neurosurgeon,
radiation oncologist, and radiation oncology
physicist, in addition to appropriate support
staff. SRS can be delivered using a
conventional or modified linear accelerator
(LINAC) system, a Gamma Knife, or a
robotically controlled miniaturized linear
accelerator (CyberKnife).
In LINAC radiosurgery circular or oval
collimators ranging from 4 to 40 mm are used
to collimate the treatment beam into a
circular pencil beam, and treatment is
delivered using multiple noncoplanar arcs
that intersect at a single point to treat an
approximately spherical target of <4 cm in
diameter.
51. Fractionated Stereotactic Radiotherapy
For lesions larger than 4 cm and/or located in critical regions, the delivery of a single large-fraction treatment as in
SRS is not desirable because of a high risk of CNS toxicity. Fractionated stereotactic radiotherapy (FRST) is a hybrid
between conventionally fractionated radiotherapy and SRS that combines fractionation with stereotactic
localization and targeting techniques.
Heavy Charged Particles
Heavy-charged-particle beams deposit their dose at a depth that depends on their energy over a distance of few
millimeters when the heavy charged particles come to rest, the so-called Bragg peak.To cover a larger volume, the
particle beam can be modulated, in effect adding up multiple Bragg peaks.The very sharp dose gradient at the
distal edge permits the use of high-dose radiotherapy for tumors in critical locations, such as at the clivus and base
of skull, and provides better normal-tissue sparing in other situations, especially, for example, in craniospinal
irradiation.
52. Brachytherapy and Radiocolloid Solutions
Selection criteria for brachytherapy include tumor confined to one hemisphere, no transcallosal or
subependymal spread, small size (<5 to 6 cm), well circumscribed on CT or MRI, and accessible
location for the implant. A balloon-based system, GliaSite , placed into the cavity at the time of
surgery has been employed in the treatment of recurrent malignant gliomas whose largest spatial
dimension is <4 cm and are roughly spherical.30 After treatment planning the balloon is filled with a
liquid that contains organically bound iodine-125 (125I), and treatment is completed within 3 to 7 days.
Direct infusion of radioimmunoglobulins has been used in primary and recurrent brain gliomas.
53.
54. CHEMOTHERAPY AND TARGETED AGENTS
Conventional Chemotherapy
• Many conventional chemotherapy agents do not adequately penetrate normal or non-enhancing tumor
infiltrated brain, whereas some drugs, despite having a molecular weight and chemical structure that
them appear capable of crossing the BBB, are p-glycoprotein and other active transporter substrates
are actively effluxed out of the brain parenchyma.
• Even when drug delivery is adequate, most CNS tumors are resistant to most chemotherapeutic agents.
Alkylating agents such as carmustine (BCNU) and lomustine (CCNU) have been the most widely studied
drugs in CNS tumors.
• These agents cross the BBB, but prolonged use is difficult because of cumulative myelotoxicity and the
dose-related risk of pulmonary fibrosis. Temozolomide, an oral agent with excellent bioavailability, has a
good toxicity profile and is the only agent to demonstrate a survival benefit for glioblastoma patients in
randomized clinical trials.
55. Direct Delivery of Therapeutic Agents
• Methods for circumventing the BBB include implantation of slow-release chemotherapy
into a tumor resection cavity, pharmacologic or osmotic BBB disruption, and convection
drug delivery (CED).
• CED involves the use of intracerebrally implanted catheters to deliver a drug into the brain
parenchyma or tumor at a slow but continuous rate of flow. Unlike diffusion, in which a drug
distributes along an exponentially decaying concentration gradient depending on the size of
molecule, drug distribution by CED is less size dependent, occurs over a larger volume of brain
tissue, and results in a more uniform drug concentration within the volume of distribution.
56. • Large and/or hydrophilic agents that do not cross the BBB are ideal candidates for delivery via CED.
Examples of agents used in CED studies include viruses, paclitaxel, topotecan, and a variety of
engineered, targeted protein toxins.
• BCNU impregnated in a polymer and made into a wafer has been used for local delivery, placed on the
walls of the resection cavity at the time of surgery.The wafer slowly undergoes biodegradation,
releasing the active drug.This local delivery system has the advantages of minimal systemic toxicity,
no limitation posed by the BBB, and delivery of very high local concentrations of chemotherapy.
Studies in glioblastoma multiforme (GBM) have shown only marginal benefit.
TargetedAgents
These include agents that block angiogenesis (vascular endothelial growth factor receptor); proliferation, tumor cell
invasion, and survival (EGFR); and cell survival (platelet-derived growth factor receptor); as well as inhibitors of
downstream signaling molecules such as Akt, Ras, Raf kinase, and mTOR.
59. a) Overview of Glial Cells
-A glioma is a primary CNS tumor that arises from a glial cells , glial cells
include astrocytes , oligodendrocytes , ependymal cells and choroid
cells
-Astrocyte :
*The normal functions of an astrocyte are to provide biochemical support
the endothelial cells that maintain the blood brain barrier , to maintain
extracellular ion balance and to aid in repair after a neuronal injury
*Astrocytes are normally located throughout the entire brain (primarily in
white matter) and spinal cord
60. -Oligodendrocyte :
*The normal function of an oligodendrocyte is to maintain myelin around
CNS axons , a single oligodendrocyte can maintain the myelin of
of axons
*The counterpart in the peripheral nervous system is the Schwann cells ,
which maintains myelin around a single peripheral nerve , unlike the
oligodendrocytes , each Schwann cell is in charge of only single axon
*Oligodendrocytes are normally located throughout the entire brain and
spinal cord
61. -Ependymal Cells :
*The normal function of an ependymal cell is to circulate CSF with its
cilia
*Ependymal cells line the ventricles and central canal of the spinal cord
-Choroid Plexus Cells :
*The normal function of a choroid plexus cell is to produce CSF , a choroid
plexus cell is a modified ependymal cell
*Choroid plexus cells are located intraventricularly , in the body and
horn of each lateral ventricle , roof of the 3rd ventricle and roof of the
ventricle
62. b) Incidence :
-Most common primary brain tumors
c) Types :
1-Astrocytomas (most common glioma , 80%)
2-Oligodendroglioma , 5%-10%
3-Ependymal Tumors
4-Choroid Plexus Tumors
63. a) Incidence :
-Astrocytomas represent 80% of gliomas
-Most tumors occur in cerebral hemispheres in adults
-In children , posterior fossa and hypothalamus / optic chiasm are more common
locations
-The differentiation of types of astrocytoma is made histologically not by imaging
b) Associations :
1-Tuberous sclerosis
2-Neurofibromatosis
1-Astrocytomas :
64. c) Classifications :
(i) Fibrillary Astrocytomas :
1-Astrocytoma , WHO grade I (AI)
2-Astrocytoma , WHO grade II (AII)
3-Anaplastic Astrocytoma , WHO grade III (AA III)
4-Glioblastoma Multiforme , WHO grade IV (GBM IV)
5-Brain stem Glioma
(ii) Other Astrocytomas :
1-Multicentric (Multifocal) Glioma
2-Gliomatosis Cerebri (Grade IV)
3-Juvenile Pilocytic Astrocytoma (Grade I)
4-Giant cell astrocytoma (in tuberous sclerosis) , (Grade I)
5-Xanthoastrocytoma (Grade I)
6-Gliosarcoma (Grade IV)
65. 1-Astrocytoma , WHO grade I (AI) :
-Focal
-Hemorrhage & edema are rare
-Hypo in T1 , Hyper in T2 with no enhancement
2-Astrocytoma , WHO grade II (AII) :
a) Incidence
-Low grade infiltrative astrocytoma (diffuse astrocytoma)
-Represent 20% of all astrocytomas
-Peak age : 20 to 40 years
-Primary location is in the cerebral hemispheres
66. 3-Anaplastic Astrocytoma (AAIII) :
a) Incidence
-Represent 30% of all astrocytomas
-Peak age: 40 to 60 years
-Primary location is in the cerebral hemispheres
4-Glioblastoma Multiforme (GBM IV) :
a) Incidence :
-Most common primary brain tumor (represents 55% of astrocytomas)
-Age: > 50 years
-Primary location is in the hemispheres :
Frontal lobe (genu)
Tempero-Occipital (splenium)
The histopathologic features of GBM include nuclear atypia, mitotic activity, vascular
and necrosis; any three of these suffice to make the diagnosis.
67. b) Tumor Spread :
-Tumor may spread along the following routes :
1-White Matter tracts
2-Across midline via commissures (e.g. corpus callosum) , i.e. butterfly glioma
(D.D. of transcallosal mass is : GBM , lymphoma & demyelinating disease)
3-Subependymal seeding of ventricles
4-CSF seeding of subarachnoid space
Pretreatment patient and tumor characteristics such as age at diagnosis,
histology, and Karnofsky performance status (KPS) are the best predictors of
outcome. Extent of resection, duration of neurologic symptoms, and
radiographic response to treatment have also been suggested as predictors of
survival.
68. Transependymal spread of GBM , T1+C shows extensive abnormal enhancement primarily in the left
occipital lobe but extending into the bilateral periventricular frontal lobes via the subependymal surface
(arrows)
69. Treatment
Standard treatment consists of maximal safe surgical resection followed by radiotherapy with
concurrent temozolomide chemotherapy and subsequent adjuvant temozolomide chemotherapy.
Other approaches including alterations in the delivery of radiotherapy, newer chemotherapeutic
agents, and radiosensitizers, and other agents are the subject of ongoing research.
Randomized trials have demonstrated a clear survival benefit to the use of radiotherapy after
surgery. Localized irradiation volumes are recommended despite the fact that GBM is usually more
widely disseminated. Dandy, for example, identified recurrences in the contralateral hemisphere
even after hemispherectomy, showing the phenomenal capability of malignant gliomas to spread
along white matter tracts.
70. Inclusion of all radiographic evidence of tumor and associated edema with generous margins
is the rule in the design of treatment portals.
Standard therapy is a total dose of 60 Gy in 30 to 33 fractions.
Walker et al.77 reported a dose–response analysis using data from 420 patients treated on
Brain Tumor Cooperative Group protocols. Doses ranged from <45 to 60 Gy, using daily
fractions of 1.7 to 2 Gy; only one-third of the patients received <60 Gy. A significant
improvement in median survival from 28 to 42 weeks in the groups treated with doses of 50
to 60 Gy was found.
A Medical Research Council study of 443 patients also showed a significant survival
advantage in patients who received 60 Gy compared to those who received 45 Gy (12 vs. 9
months; p = .007).
71. Dose Escalation and Altered Fractionation
A benefit for doses >60 Gy using conventional treatment has not been demonstrated. The RTOG
and Eastern Cooperative Oncology Group (ECOG) randomized 253 patients to either whole-brain
irradiation to 60 Gy given in 6 to 7 weeks or 60 Gy plus a 10-Gy boost to a limited volume given in 7
to 8 weeks.79 There was no benefit for the higher irradiation dose. Median survival was 9.3 months
for patients receiving 60 Gy and 8.2 months for those receiving 70 Gy.
Several groups have used hyperfractionated or accelerated regimens as a means to escalate dose,
using twice-daily, three-times-daily, and even four-times-daily fractionation. Only the study of Shin et
al.showed an improvement in survival using daily fractionation. In this study, 81 patients were
randomized to 61.4 Gy in 69 fractions of 0.89 Gy given three times daily over 4.5 weeks or
conventional fractionation to 58 Gy in 30 fractions given once daily over 6 weeks. Median survival
in the two groups was 39 and 27 weeks, respectively, and the 1-year survival rates were 41% and
20%, respectively (p < .001).
Others have failed to confirm these results.
72. Dose Escalation Using Radiosurgery and FSRT
A radiosurgical boost was reported as effective in patients with newly diagnosed malignant glioma in a
retrospective analysis of 115 patients treated at three institutions with a combination of surgery, external-
beam radiotherapy, and LINAC-based radiosurgery on similar institutional protocols.The actuarial 2- year
and median survival for all patients was 45% and 96 weeks, respectively. In comparison to results for 1,578
patients treated on three RTOG external-beam radiotherapy protocols from 1974 to 1989, patients treated
with radiosurgery had significantly improved 2-year and median survival.
Dose Escalation Using Brachytherapy
Laperriere et al. used brachytherapy as a boost to conventional radiotherapy in patients with malignant
gliomas. Patients were randomized to external-beam radiotherapy (50 Gy in 25 fractions) alone (n = 69) or
external-beam radiotherapy plus a temporary stereotactic 125I implant delivering a minimum peripheral
tumor dose of 60 Gy (n = 71). Median survival was not significantly different between the two arms (13.8 vs.
13.2 months; p = .49).
The results of the Brain Tumor Cooperative Group National Institutes of Health Trial 8701 reported by Selker
et al.93 support these findings. In this randomized, prospective trial, 299 patients with newly diagnosed
malignant glioma received surgery, external-beam radiotherapy, and BCNU with or without an interstitial
radiotherapy boost with 125I. Treatment with an interstitial boost did not prolong survival as compared to
conventional treatment.
73. Chemotherapy
The use of cytotoxic chemotherapeutic agents for glioblastoma dates back to the 1960s when the Brain
Tumor Study Group conducted a controlled study using carmustine. After surgery, patients were assigned to
one of four treatment groups: (a) no further therapy, (b) carmustine alone, (c) radiation therapy, and (d)
radiation therapy followed by carmustine. At 18 months 23% of patients who received radiation therapy plus
carmustine were still alive as compared to 5% with carmustine or radiotherapy alone.
The only chemotherapeutic agent that has demonstrated efficacy in a randomized, controlled clinical trials is
temozolomide, an oral imidazotetrazine derivative of dacarbazine that is metabolized in vivo to an active
agent. Like the nitrosureas, it alkylates the O6 position on guanine, producing single-strand DNA breaks. It is
well tolerated by patients; fatigue, constipation, and nausea are the most common toxicities. The drug is
myelosuppressive in a minority of patients. Approval for the treatment of recurrent anaplastic astrocytoma
was obtained from the FDA in 1999 based on the work of Yung et al.103 Its approval for use as adjuvant
therapy for glioblastoma was based on a large phase III clinical trial conducted by the
EORTC and the National Cancer Institute of Canada (NCIC).
74. The survival benefit from the addition of temozolomide has now been demonstrated for at least
5 years out from initial treatment and in all clinical prognostic subgroups, including patients aged
60 to 70 years. Five-year overall survival was 9.8% for patients who received combined
temozolomide and radiotherapy as compared to 1.9% for those who received radiotherapy alone.
Treatment Summary
1. Maximal surgical resection, although not tested in a prospective trial, is generally fit.
2. Postoperative radiotherapy has been shown to provide a survival advantage in several clinical
trials. The typical radiotherapy dose is 60 Gy in 6 weeks; dose escalation strategies have
generally failed. Although there is much interest in incorporating advanced imaging in treatment
planning and in using newer treatment modalities, their benefits in GBM remain to be
demonstrated.
3. Temozolomide, given during and after radiotherapy, provides a significant survival advantage
that is greatest in patients with methylation of the promoter region of the MGMT gene.
75. 1-Multicentric (Multifocal) Glioma :
-The actual incidence of true multicentric glioblastoma multiforme (GBM) varies
between 2.4 and 4.9% of all GBMs
-True multicentric tumors are described as widespread lesions in different lobes
hemispheres
-Differential Diagnosis : From Metastases (but metastases is more common)
OTHERS:
76. a) Definition :
-Diffusely infiltrative glial tumor that involves at least three lobes
definition plus extra-cortical involvement of structures such as
basal ganglia , corpus callosum , brainstem or cerebellum
-Usually there are no gross mass lesions
-There often is an important discordance between clinical and
radiological findings as it may be clinically silent while it
a very extensive process radiologically
2-Gliomatosis Cerebri :
77. b) Incidence :
-Age : 30 to 40 years
-Rare
-WHO (Grade IV)
TREATMENT
1. Maximal surgical resection is not an achievable goal.
2. Radiotherapy is considered the standard, but no trials have validated its role.
3. The role of chemotherapy remains ill defined.
78. 3-Juvenile Pilocytic Astrocytoma :
a) Incidence :
-Most common in children (represents 30% of pediatric gliomas)
-Second most common pediatric brain tumor
-WHO Grade I
b) Location :
-Most common location is the cerebellum
-Vermis (50%) or hemispheres (20%) or both sites (30%)
-In general they typically arise from midline structures :
1-Optic nerve / optic chiasm ( 25-30% ) , very common location in NF1
2-Hypothalamic / adjacent to third ventricle
3-Brainstem
C) Treatment Summary
■ 1. Maximal surgical resection, although not tested in a prospective trial, is associated with more
favorable outcome and is recommended whenever feasible.
■ 2. Postoperative radiotherapy may be considered in patients with incompletely resected tumors, based
on risk factors for progression and consequences of progression.
■ 3. Chemotherapy does not have an established role in pilocytic astrocytoma in adults.
79. 4-Pleomorphic Xanthoastrocytoma :
a) Incidence :
-Type of rare low grade astrocytoma (WHO Grade I)
-Typically these tumors are found in young patients (children or young adults) and as they
have a predilection for the temporal lobe, they most frequently present with temporal
lobe seizures
b) Location :
-PXAs are almost invariably (98%) located supratentorially , typically located superficially
(peripherally) involving the cortex and overlying leptomeninges
-Approximately half are located in the temporal lobe
80. 5-Gliosarcoma :
a) Incidence :
-Are rare highly malignant (WHO grade IV) primary intra-axial neoplasms
-They are often considered a histological variant of glioblastoma multiforme
(GBM)
-Peak presentation is around the 6th decade
-The tumor is very similar to (GBM) but with an added sarcomatous component
(the tumor comprises of both glial and mesenchymal elements)
b) Radiographic Features :
-Can be very similar to glioblastoma multiforme (GBM)
-There may be slight predilection towards the temporal lobes
-May demonstrate dural invasion
81. OLIGODENDROGLIOMA :
a) Incidence :
-These are usually tumors of middle-aged adults occurring most commonly in the 4th and 5th
decades of life
-Due to their usual cortical involvement , presentation is most frequently as a result of seizure
b) Types :
1-Oligodendroglioma (WHO grade II / low grade)
2-Anaplastic Oligodendroglioma (WHO grade III / high grade) , much more aggressive than
oligodendroglioma
3-Oligoastrocytoma (mixed oligodendroglioma and astrocyoma) , much more aggressive than
oligodendroglioma
c) Location :
-Tumors are typically located supratentorially (85%) involving the white matter and overlying cortex
-They are most commonly found in the frontal lobes
82. EPENDYMAL TUMORS :
a) Types :
-The ependyma refers to a layer of ciliated cells lining the ventricular
walls and the central canal
-There are several histologic variants of ependymal tumors:
1-Ependymoma (children)
2-Subependymoma (older patients)
3-Anaplastic Ependymoma
4-Myxopapillary Ependymoma of Filum Terminale
5-Ependymoblastoma (PNET)
83. Ependymoma :
1-Incidence :
-Most common in children
-Age : 1 to 5 years
2-Location :
-Usually located in or adjacent to ventricles within the parenchyma
-The majority of intracranial ependymomas (60%) are located in the posterior fossa
(infratentorial) usually arising from the floor of the fourth ventricle , this is especially true
in children
-The remainder (40%) are located supratentorially and up to half of these are
intraparenchymal
84. a) Floor of the fourth ventricle , 70% (commonest location in children)
b) Lateral ventricle or periventricular parenchymal , 30% , more common in adults
c) Spinal cord ependymoma (in adults)
d) Supratentorial ependymoma
3-Association :
-Spinal ependymomas are associated with neurofibromatosis type 2 (NF2)
85. 4-Radiographic Features : Heterogenous
1-CT :
-Growth pattern depends on location :
a) Supratentorial : tumors grow outside ventricle (i.e. resembles astrocytoma)
b) Infratentorial : tumors grow inside 4th ventricle and extend through foramen of Luschka into
CPA and cisterna magna , this appearance is characteristic (plastic ependymoma) and
often helps to differentiate an ependymoma from a medulloblastoma
-Hydrocephalus is virtually always present when in posterior fossa
-Fine calcifications , 50%
-Cystic areas , 50%
-Heterogenous enhancement
-A small proportion can have hemorrhage
86. TREATMENT SUMMARY
1. Maximal surgical resection should be performed when feasible.
2. Postoperative radiotherapy is considered the standard. There appears to be a radiation dose
response, with improved tumor control with doses >50 Gy, and doses of 54 to 59.4 Gy are typically
prescribed.
, but no prospective trials have validated its role. Craniospinal irradiation is used only in patients
with disseminated disease.
3. The role of chemotherapy remains to be defined.
87. Subependymoma :
1-Incidence :
-Middle aged to older individuals ( typically 5th to 6th decades )
-Asymptomatic fourth ventricular tumor found in elderly males
2-Location :
-2/3 arise in the fourth ventricle (inferior 4th ventricle)
-1/3 in lateral ventricles (foramen of Monro)
88. Choroid Plexus Papilloma / Carcinoma
:a) Incidence :
-Peak age : < 5 years (85%)
-Most common brain tumor in babies < 1 year old , but it may also occur in adults
-90% represent choroid plexus papilloma (WHO I) , 10% choroid plexus carcinoma
(WHOIII)
b) Location :
-Unlike most other brain tumors which are more common in the posterior fossa in
children and supratentorial compartment in adults , the relationship is reversed for
choroid plexus papilloma
-In adults these tumors most often (70%) occur in the fourth ventricle , In the pediatric
age group the lateral ventricles are the commonest location with a predilection for
the trigone
89. Meningeal and Mesenchymal Tumors :
a) Meningioma
b) Meningeal Hemangiopericytoma
c) Hemangioblasotma
90. Meningioma :
1-Incidence :
-Most common extra-axial tumor
-Age: 40 to 60 years
-Three times more common in females
-Represents 20% of all brain tumors
-Meningiomas are uncommon in children and if present are commonly
associated with NF2
-90% are supratentorial
-Multiple meningiomas are seen in NF2 or following radiation therapy
91. 2-Classification :
a) Typical (benign) meningioma , 93% (WHO I)
b) Atypical meningioma , 5% (WHO II)
c) Anaplastic (malignant) meningioma , 1%-2% (WHO III)
d) Meningioma with sarcomatous degeneration , extremely rare
94. TREATMENT SUMMARY
1. Small asymptomatic meningiomas in noncritical locations, especially in the elderly or in patients with other
comorbidities, can be observed.
2. The goal of surgery is to completely resect the meningioma with negative margins, as patients with WHO
grade I completely resected meningiomas have low rates of relapse and can be observed postoperatively.
3.For subtotally resected or unresectable progressive meningioma radiotherapy is frequently used but has not
been tested in a prospective clinical trial. Local control appears to be improved with postoperative radiotherapy.
Both radiosurgery and radiotherapy have been used in this context but have not been directly compared.
4.For grades II and III meningioma, postoperative radiotherapy is routinely recommended.
5.Primary radiotherapy or radiosurgery could be used for unresectable, progressive meningiomas.
6.Systemic therapy does not have a defined role in meningioma.
95. Neuronal & Mixed Glial / Neuronal
Tumors
a) Ganglioglioma / Ganglioneuroma
b) DNET
c) Central Neurocytoma
96. a) Ganglioglioma / Ganglioneuroma :
1-Incidence :
-Benign neoplasm of children / young adults with glial and neural elements
-Low grade and slow growing (WHO I)
-Often presents with seizures
2-Location :
-Temporal > frontal > parietal
-The most common presentation is with temporal lobe epilepsy , presumably due to the
temporal lobes being a favored location
97. b) Dysembryoplastic Neuroepithelial Tumor
(DNET) :
1-Incidence :
-Occurs in younger patients
-Low grade (WHO I)
-Strongly associated with epilepsy
2-Location :
-Temporal lobe is common (>60%) and the lesion often involves or
lies close to mesial temporal structures
-Other locations include frontal lobe followed by parietal and/or
occipital lobes
98. c) Central Neurocytoma :
1-Incidence :
-Typically seen in young patients (20 - 40 years of age)
-Accounts for less than 1% of intracranial tumors
- WHO (Grade II) neuroepithelial intraventricular tumors with typical imaging features
2-Location :
-Lateral ventricles around foramen of Munro (most common) : 50% , It is usually attached to the
septum pellucidum when arising from the lateral ventricle
-Both lateral and 3rd ventricles : 15%
-Bilateral : 15%
-3rd ventricle in isolation : 5%
99. Primary CNS Lymphoma (PCNSL) :
1-Incidence :
-1% of brain tumors , typically patients diagnosed with PCNSL are over the age
of 50
-Usually B-cell non Hodgkin's lymphoma (NHL)
-High incidence in immunocompromised hosts :
a) HIV : approximately 2-6% of patients with HIV will develop PCNSL
b) Prior EBV infection
c) Post transplantation
d) IgA deficiency
-PCNSL is known to (melt away) with chemoradiation but tends to recur aggressively
100. 2-Location :
-Supratentorial (75-85%)
a) Basal ganglia , 50%
b) Periventricular deep WM
c) Corpus callosum , mimics butterfly glioma
TREATMENT SUMMARY
■ 1. Surgical resection is not necessary.
■ 2. Avoiding or deferring WBRT results in inferior progression-free survival but without significantly affecting overall survival.
Because of the toxicities associated with WBRT, its role is being evaluated in a risk-adapted approach by the RTOG.
■ 3. High-dose systemic methotrexate is the only agent that has demonstrated improved survival over WBRT alone. High-
dose methotrexate–based chemotherapy followed by whole-brain radiotherapy is the standard treatment for patients
younger than 60 years of age with a good performance status.
■ 4. High-dose methotrexate–based chemotherapy alone with deferred radiotherapy may be preferred in elderly patients
because of substantial risk of neurotoxicity associated with combined chemotherapy– radiotherapy regimens.
101. Secondary CNS Lymphoma (SCNSL) :
1-Incidence :
-15% in patients with systemic lymphoma
-Typically a non-Hodgkin lymphoma and by definition has
systemic disease at the time of presentation with
secondary involvement of the central nervous system
-Unlike primary CNS lymphoma it more commonly involves
the leptomeninges and is uncommonly detectable on
CT/MR with malignant cells found of CSF aspiration
102. Craniopharyngioma
■ arise from epithelial remnants of the Rathke pouch and are typically found in the suprasellar
region in children or adolescents. They account for <5% of all CNS neoplasms in adults. They are
slowly growing tumors that often have solid and cystic components, the latter filled with lipoid,
cholesterol-laden (“crankcase oil”) fluid.
■ Intrasellar lesions may compress the pituitary gland and hypothalamus, producing hormonal
abnormalities, especially antidiuretic and growth hormone deficits.
■ Prechiasmal lesions may compress the optic pathway, leading to visual field cuts or decreased
central visual acuity.
■ Retrochiasmal lesions may grow into the third ventricle and cause hydrocephalus or compress
the optic tracts.
■ Craniopharyngiomas can occasionally reach enormous size and produce neurologic impairment
by direct impingement on brain parenchyma.
103. Treatment Summary
1. Surgical resection is recommended, when feasible.
2. The use of postoperative radiotherapy has not been tested in prospective trials but reduces the risk of
recurrence and improves survival in incompletely resected tumors. Cyst decompression and biopsy followed
by radiotherapy may be an acceptable treatment for patients for whom resection is not considered feasible.
3. Intracavitary bleomycin or radiocolloids may be useful in cystic tumors.
104. SEQUELAE OF TREATMENT
Surgery
• With appropriate patient selection, diligent surgical technique, and use of surgical adjuncts such as speech
and/or motor mapping, the rate of complications can be minimized.
• Even in the best of hands new temporary neurologic deficits can be seen in 15% or more of patients,
although the rate of permanent new deficits is typically now <5%.
• The incidence and types of deficits seen following surgery depend upon the location of the tumor and the
deficits present preoperatively.
• The most common complications associated with surgery are bleeding and infection, particular in the case of
reoperation in a patient who has received prior radiotherapy and/or chemotherapy or when chemotherapy
wafers are placed into a resection cavity.
105. Radiotherapy
The response of intracranial tissues to radiation has been classically divided into three phases based on the
timing of onset of symptoms: acute, subacute, and late.
Acute Toxicity
• Transient worsening of pretreatment deficits may develop during the course of treatment, and further acute
toxicities may manifest up to 6 weeks following completion of irradiation.
• These symptoms are believed to be the consequence of a transient peritumoral edema and usually respond
to a short-term increase or the institution of corticosteroids.
• Persistent or refractory symptoms may be caused by tumor progression, and repeat imaging while under
treatment may be indicated if the clinical condition worsens despite steroids.
• General symptoms such as fatigue, headache, and drowsiness may be seen, especially in individuals treated
with large brain fields or with CSI.
• A mild dermatitis and alopecia that develops in irradiated areas may be treated with topical agents if
necessary.
• Nausea and vomiting independent of changes in intracranial pressure may occur
106. • Otitis externa can be seen if the ear is included in the irradiation fields, and serous otitis media
also may occur. Patients treated with CSI with photons are at risk for mucositis and esophagitis
because of the exit dose from the spinal fields through the oropharynx and mediastinum.
Hematologic toxicity may also be seen in these patients due to irradiation of the vertebral
bodies, a major depot of bone marrow in adults.
Subacute Toxicity
• Subacute or “early-delayed” toxicity that develops during the 6-week to 6-month period following irradiation
is attributed to changes in capillary permeability, as well as to transient demyelination due to damage to
oligodendroglial cells.
• Symptoms, which include headache, somnolence, fatigability, and deterioration of pre-existing deficits,
usually respond to steroids.
• The main challenge is to distinguish the clinical and imaging findings from tumor recurrence.
• The phenomenon of pseudoprogression temporally fits within the subacute toxicity time frame.
107. Late Sequelae
• Late sequelae of radiotherapy appear from 6 months to many years following treatment and are usually
irreversible and progressive.
• They are believed to be due to white matter damage from vascular injury, demyelination, and necrosis. The
most serious late reaction to radiotherapy is radiation necrosis, which has a peak incidence at 3 years.
• Radiation necrosis can mimic recurrent tumor clinically by the reappearance and worsening of initial
symptoms and neurologic deficits and radiographically with the development of a progressive, irreversible,
enhancing mass with associated edema on imaging. PET, MR spectroscopy, and nuclear and dynamic CT
scanning procedures may aid in the differentiation of radiation necrosis from recurrent tumor.
• The best treatment for symptomatic necrosis is control of symptoms with steroids, followed by surgical
debulking, although even after resection necrosis may progress.
108. • Inclusion of the middle ear may result in high-tone hearing loss and vestibular damage, especially in patients
who receive cisplatin. Retinopathy or cataract formation may be seen if the eye is in the radiation field.
• Optic chiasm and nerve injury may manifest as a decrease in visual acuity, visual field changes, or blindness
at doses >54 to 60 Gy. Onset of hormone insufficiency from irradiation of the hypothalamic– pituitary axis is
variable but may be seen with doses as low as 20 Gy.
• Cranial irradiation can produce neuropsychologic changes and neurocognitive impairment; other factors,
such as tumor-related morbidity, as well as the effects of surgery and chemotherapy, may also contribute.
• Hippocampal-dependent functions of new learning, memory, and spatial information processing appear to
be most affected
