CNS Oncology & RT Flashcards
how many brain tumours are primary
80%
how many brain tumours are mets
20%
what does survival depend on
guaranteed survival or guaranteed fatality
how many types of brain tumour are there
130
what is the most common type of brain tumour
GBM
where can brain tumours be found
extra-axially and intra-axially
what are brain tumours graded on
genetic findings
PS + fitness
extent of spread
tumour type
location
tumour left after surgery, the amount affects the grade and outcome
what is extra-axial
outside the brain
meningioma, acoustic neuroma
what is intra-axial
inside the brain
glioma
what information enhances treatment options
genetics
what genetics can be looked at
gaining or losing a chromosome, could swap position with other DNA
DNA mark up can change its behaviour
what is MGMT responsible for
cell repair
tumours have a high level, rapid cell repair therefore damage to cell via treatment is less effective
what is EGFR
Epidermal Growth Factor Receptor
protein involved in cell repair
what is IDK
isocitrate dehydrogenase
provides instructions for making a protein involved in cellular metabolism [energy production, cell repair can occur, harder to treat]
what is a seizure
an abnormal electroactivity burst within the brain
how are CNS tumours staged
using the 5th edition of WHO classification
no N stage [TNM IS NOT USED]
molecular grading: low grades can still be aggressive with some molecular subtypes
what are presenting symptoms
fatigue
confusion
sensitivity to light
pain
aching
eye movement issues
heavy body
early/late puberty
nausea & vomiting
balance issues
seizures
changes in head circumference
poor vision
headaches
throbbing head
what are some parietal presentations
visuo-spacial processing issues
knowledge of numbers
spelling
perception issues
object classification
processing info issues, close to the outside of the brain
how are they diagnosed
biopsy not always possible
imaging
MRI
CT [extra-axial]
PET-CT
how is a tumour properly diagnosed
imaging, lumbar puncture, angiography
why is a angiography useful
determines if the tumour has its own blood supply, identify any blockage
however it is unreliable for brain tumours
what is the job of the lumbar puncture
identify if there is any micromets present within the CSF fluid [determine spread]
what are the side effects/ management for CNS
short term memory loss
confusion
loss of fine motor skills
headaches = medication
dizziness
funny smell [irradiated olfactory nerve]
altered PS
vision changes
nausea and vomiting
balance and coordination
seizures = medicine
fatigue
hair loss
how are side effects managed
steroids
anti-convultants i.e keppra
SLT
antisickness
counselling
family support
physiotherapy
consent [Mental Health Capacity Act 2005]
what is the mental capacity act
understand info about decision
remember the info
consider in the decision making process
communicate their decision
what are gliomas
a group of tumours, which arise from glial cells the most common are astrocytes and oligodendrocytes
what are gliomas characterised on
the genetic mutation
DNA mark up is important
what are the types of gliomas
astrocytoma
ogliodendroglioma
gliobastoma
what is an astrocytoma
tumour from astrocyte cells, found in WM, the EGFR is high which promotes tumour growth
what is a grade 1 astrocytoma
pilocytic astrocytoma:
slow growing
cerebellum/optic pathway
well defined edges within capsule
good for surgical removal, low risk of recurrence
occur in <20
what is a grade 2 astro
diffuse astro
undefined edges
20-45
can cause a recurrence, a recurrent grade 2 = grade 3
what is a grade 3 astro
anaplastic:
rapid division
often recur to become grade 4 glioma
30-70
might need a debulking treatment
what is a ogliodendroglioma
occurs from the oligodendrocytes [conductor between neurons]
40-60
2-5% of primary CNS
G1= rare
G2 = slow growing
G3 =. rapid growth
mostly occur on the brain but can be found in the SC
frontal and temporal are the most common lobes
seizures, convulsions, slow motor responses, behavioural changes
what genetic difference does a gliobastoma have
EGFR amplification = 40%
HGG
high grade glioma
LGG
low grade glioma
what are the different types of glioblastoma HGG
IDH wildetype
multiforme
giant cell GB
gliosarcoma
epitheloid GB
how many primary CNS are glioblastomas
54%
have a <2 year prognosis
characteristics of a HGG glioblastoma
significant damage to neurological function
diffuse infiltration to other parts of the brain
frequently crosses midline, involving the contralateral brain
resistant to treatment
HGG grow with an expanding and destructive process
where are patterns for GB found
in the subcortical WM and deep GM of the central hemispheres particularly in the temporal lobe
what is the mandatory criteria for a GBM
16+
diffuse astrocytic
IDH wildetype
what is the criteria that a GBM must have one of
necrosis
microvascular proliferation
TERT promoter mutation
EGER gene amplification
gain 7 chromosome and loss 10 chromosome
where is a primary extra-axial tumour found
outside the cerebrum
what type of tumour is a menigioma
extra-axial
describe a meningioma
slow growing
in the arachnoid layer
25% of primary CNS
presentation occurs when its highly infiltrated intracranially
what is the options for a meningioma
active monitoring
RT for symptomatic patients
surgery
NO chemo as it doesnt respond
why are skull based tumours difficult to treat
sit close to the CNS and brainstem
what tumours arise from neuromuscular structures
meningioma
pituitary adenoma
schwannoma
what tumours arise from the cranial base
chordoma
chondrosarcoma
what is a schwannoma tumour presentation
[trigeminal nerve/ vestibular schwannoma]
unilateral hearing loss = 90%
severe pain
facial numbness
brain stem compression = 60-80%
very difficult to treat
germinoma
kids + young adults
arise from germ cells
havent properly formed + migrated
spread via CSF
craniopharyngioma
near pituitary
bengin
PBT
eye/ sight problems, headaches and tiredness
ependymoma
arise from ependymal cells
SIOP II trial looks at chemo as an addition + RT extension
slow growing
surgery alone + RT
localised ependymoma = 42 days [28 is ideal]
what is the trial RT regime for ependymoma
phase I: whole CNS
36Gy in 20 >3cm
25Gy in 20 < 3
phase II: tumour bed boost + boost to met sites
up to 59.4Gy in 33 [50.4 for spine mets]
what is ependymoma presentation
neck pain, tingling in hands and neck swelling
what is the RT for ependymoma
VMAT [however there is dose issues]
54Gy in 30
what is the risks for spinal cord tumours
they are unknown apart from NF1/NF2 mutations
NF1 mutations include.
high levels of skin pigmentation
multiple tumours along spine/ brain
growth disorder
intellectual impairment
what is upper body presentation
arm weakness
respiratory
pain
pins in needles
what is lower body presentation
leg weakness
problems walking
bladder/bowel control
sexual function
pain
pins in needles
what are intramedullary tumours
within the nerves of the SC
astrocytomas and ependymomas
what are intradural extramedullary tumours
start inside the SC coverings but outside the cord not within the nerve tissue
meningiomas and schwannomas
what are extra-dural spine tumours
tumours which start within the spine bone, which is a primary
what are some benign extradural spine tumours
oesteomas and oesteoblastomas
what are some malignant extradural spine tumours
oestosarcomas, chondrosarcomas, fibrosarcomas
what is a chordoma
a tumour which arises from the base of skull or spine
it is slow growing, so it uses a watch and wait approach
if fast then surgery will occur
what is a chondrosarcoma
the most common primary bone tumour which arises from the cartilage cells
common in >40
which presents as a physical lump
what is the diagnosis for a spinal tumour
biopsy [must be safe]
blood test
lumbar puncture
bone scan [any bone mets]
where is spread likely for spine tumours
nearby tissues/ up or down the spine
brain tumour -> spine
common
spine tumour -> brain
uncommon
do spine tumours require a high or low dose
high because they are radio-resistant
SHOULDNT BE HYPOFRACTIONATED
what is the treatment for SC tumours
most common = watch and wait
debulking is only if there is a paralysis risk
if surgery cant happen RT will, also if unable to remove the entire tumour, after debulking surgery or after surgery to prevent recurrence
what type of RT is ideal
PBT
if not then SABR then SRS
protons allow for dose escalation, beam shaping however the patient must have clear surgical margins, no micro spread and no metal work
useful at sparing healthy tissue and reducing secondary malignancies
what is the PBT dose for spinal cord tumours
75.6Gy/CGE/ 42 fractions
how many hours must be given between each treatment for SBAR
40
what type of cancer is SABR for
oligo met
what is the inclusion criteria for SBAR
spinal oligo met
PS 0-2
limited systemic disease
<2 consecutive vertebral bodies involved
3-5mm away from cord
well defined
18+
histological confirmation of neoplastic disease
what is the exclusion criteria for SABR
spinal instability
unable to tolerate RT
pacemaker/metal work
prognosis< 3 months
significant or progressive neurological deficit
emergency surgery or RT
radiosensitive histology
SC compression
what is the spine doses for SABR
1 fraction = 18-24Gy
2 fractions = 24Gy
3 alt days or daily = 24-27Gy
what determines the treatment for CNS tumours
identify the tumour genetics
tumour location, size,
PS
what will be beneficial whilst reducing the impact of QOL
age
low or high risk
molecular/genetic status
LE > 12 weeks
biopsy helps identify any resistance
what happens as PS decreases
the fractionation decreases
what is the planning for CNS
CT
head in neutral = lateral
head tilt = frontal or occipital
supine + mask
protons can be done prone for posterior tumours
what is the dose constraint for BS
<54
dose constraint for retina
< 45
dose constraint for optic chiasm
<45 due to risk of blindness however can be 50-54
dose constraint for cochlea
< 50
dose constraint for lens
< 10 Gy but ideally < 6
are high or low doses needed for GBM
high as they are high grade made up of multiple cell types
whats the dose for GBM IDH wildetype good PS
60Gy in 30 in 6 weeks +/- temz
whats the dose for GBM IDH wildetype moderate PS
40Gy in 15 in 3 weeks +/- temz
whats the dose for GBM IDH wildetype low PS
34Gy in 10 fractions or 30Gy in 6 on alternate days
what treatment cant be used for craniopharyngioma
surgery
what is the fractionation for craniopharyngioma
50.1-54Gy in 30
what is the beam arrangement for craniopharyngioma
field borders
reids baseline
base of orbit EAM
sup/ant + post into air to cover whole brain
MLC = reduced dose to eye into air to reduce scatter
what is the SRS potential dependent on for meningioma
size
small volume (5mm from optic apparatus)
hypofractionated SRS for smaller meningioma <3cm 25Gy in 5
whole brain fractionation for grade 1
VMAT 50-54Gy in 25-30
SRS 13-15Gy in 1
SRS 25Gy in 5
whole brain fractionation Grade 2
54-60Gy in 30
whole brain fractionation Grade 3
60Gy in 30
what is the time period for cord comp
24 hours
fast tracked if hand numbness
48 hours if it is an accidental finding and asymptomatic
what scan is done to look at the areas need to be treated for CC
MRI/CT
whole spine
CC dose for < 6 months
8Gy in 1
CC dose for good prognosis/ post spine surgery
20Gy in 5
30Gy in 10
what is the RT technique for CC
simple open fields
single applied field
extended FSD
6/10MV (L = 10MV)
1 vertebrae above and 1 below
CT scanned, field applied on prosoma
what are the SE and management to CC RT
antisickness (field size + location)
worsening of neurological symptoms
worse tingling
increased pain
skin reaction = treating at D-max
diarrhoea
oesophagitis
what is a late effect of CC RT
radiation neuropathy
destruction of the myelin sheath, worse sensory issues
steroid SE
insomnia
low mood
mood swings
weight gain - water retention
increased appetite
prolonged use
loss of muscle mass
immunosuppression
cataracts
bone density changes
personality changes
what deletions have the worse prognosis
1p/19q
what is the dose for G2 of 1p/19q deletion
50.4Gy in 28
45Gy in 25 or 54 in 30 with adj PCV or temz
what is the dose for G3 of 1p/19q deletion
59.4Gy in 33 with adj temz
what is the dose for G4 of 1p/19q deletion
60Gy in 30 +/- concurrent + adj temz
what are the brain met treatment options
gamma knife = solitary + mets = total volume 20cm cubed
cyber knife
PBT
WBRT +/- hippocampal sparing
what are the doses for WBRT
20Gy in 5 (pall)
30Gy in 10 6MV
whole brain RT reduces QOL however disease control
what is the dose for 1 fraction SRS for <20mm
21-24
what is the dose for 1 fraction SRS for 21-30mm
18
what is the dose for 1 fraction SRS for 31-40mm
15 can also consider hypo
what is the dose for hypofraction SRS
24-27Gy in 3 daily
30Gy in 5 daily
35Gy in 5 daily
why should gamma knife not be done for volumes greater than 20
greater risks
