CNS Flashcards

1
Q

When is surgery considered as treatment for intracranial mets

A

Solitary or large met (>3cm)
Mets causing obstruction - hydrocephalus or raised ICP
Cystic or necrotic mets where SRS is less likely to be effective
Where histology / diagnosis will be helpful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the criteria for SRS

A

An established diagnosis of cancer
Karnofsky performance status (KPS) >70
Absent or controllable primary disease (staging scans within last 3 months)
No previous SRS/SRT in the last 3 months
Life expectancy from extracranial disease >6 months
No pressure symptoms best relieved by surgery
Contrast enhanced MRI to evaluate cerebral metastases
Maximum combined treatment volume <20cc
Discussion at an MDT meeting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the histological signs of a GBM

A

Epithelial / vascular proliferation
Necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the pathognomic mutation of an oligodendroglioma

A

1p19q co-deletion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the pathognomic mutation of an astrocytoma (presuming high grade ancestry)

A

ATRX loss
(ATRX retained = GBM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is bright on a T1 MRI

A

T1 -> CSF dark & Tumour dark

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is bright on T2 MRI & FLAIR

A

T2 -> CSF white & Tumour bright
T2 FLAIR -> CSF dark & Tumour bright with Oedema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do low & high grade tumours enhance with contrast

A

Low grade tumours tend not to enhance. High grade tumours enhance (due to endothelial / vascular proliferation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where and for whom do pilocytic astrocytomas occur, and how do they present

A

Typically in children, low grade tumour
Tend to occur in cerebellum, causing obstruction and obstructive symptoms (pressure sx and headache)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the dose fractionation for craniospinal irradiation for a non-germinoma

A

overall 54Gy/30#
36Gy/20# to whole CSA and 18Gy/10# boost to tumour bed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the most common mutations seen in a pleomorphic xanthoastrocytoma

A

CDKN2A/B deletions (>90 percent)
BRAF V600E mutations (60-80 percent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the benefit of adjuvant PCV in grade 2 gliomas

A

Buckner - 2016 NEJM
high risk Gr2 gliomas (<40yrs and subtotal resection or >40yrs) randomised to 6x adj PCV or not
PCV increased mOS to 13.3yrs from 7.8, and 10yr OS from 40% to 60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When is immediate post-op RT indicated for a grade 2 glioma, vs at progression?

A

2 of:
Age >40
>6cm
Enhancement
Astrocytic
Crossing midline
Symptomatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the adjuvant RT dose for a low grade glioma

A

54Gy/30#

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the adjuvant dose for a grade 3 anaplastic oligodendroglioma

What adjuvant chemotherapy regime would typically follow

A

59.4/33#

Followed by 6x PCV adjuvant chemotherapy

12mth OS benefit to PCV adjuvantly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the adjuvant dose for a grade 3 anaplastic astrocytoma

What adjuvant chemotherapy regime would typically follow

A

59.4Gy/33#

Temozolamide x12 cycles adjuvantly
Based on the catnon trial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the post-operative RT regimen for a Gr4 GBM if <70 and PS0-1

And if <70 & PS2

And if >70

A

Concomitant CRT
60Gy/30# + concurrent TMZ (75mg/m2) & Co-trimoxazole prophylaxis 480mg M/W/F

Adjuvant chemotherapy
Adjuvant TMZ 150 - 200mg/m2 - D1-5 Q28 for 6 cycles

If <70 but PS2 - give RT only, without temozolamide

> 70: 40Gy/15# +/- concomitant tmz, and based on methylation status (based on Perry trial)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What RT dose is given to a butterfly glioma

A

30Gy/6# over 2wks, treating M/W/F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the mOS for a GBM? and based on what trial

A

Stupp trial
CRT & adj tmz vs RT alone
Median OS: 14.6m vs 12m and PFS 6.9m vs 5m
2yr OS: 26.5% vs 10.4%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Diffuse midline H3 K27-altered midline gliomas area considered what grade

Where are they typically located

How do they typically present

A

Always grade 4

most commonly in the pons, or other midline structures
(thalamus, brainstem - mesencephalon, pons, medulla, spinal cord)

Present with CN palsies, raised ICP and cerebellar sx.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the dose objective & constraint to brainstem

A

54Gy (objective)
59Gy (constraint)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the dose constraint to spinal cord

A

48Gy (objective)
50Gy (constraint)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the dose objective & constraint to optic nerves

A

50Gy (objective)
54Gy (constraint)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the dose objective & constraint to optic chiasm

A

50Gy - objective
54Gy - constraint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the dose objective & constraint to lens

A

6Gy objective
10Gy constraint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the dose objective & constraint to globes

A

O - 40Gy
C - 45Gy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the dose constraint to cornea

A

30Gy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the dose objective & constraint to retina

A

O - 45Gy
C - 50Gy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the dose constraint to lacrimal gland

A

Mean <26Gy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the dose constraint to cochlea

A

Mean <45Gy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the acute side effects of brain RT

A

Alopecia
Headache
Nausea/vomiting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the late side effects of brain RT

A

Neurocognitive effect – memory loss
Pituitary hypofunction
Optic chiasm damage – may cause blindness
Cataracts
2nd malignancies = 1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the most common malignant tumour of the eye and ocular adenexa.

A

Non-hodgkin lymphoma - treat as primary CNS lymphoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Where do ependymomas originate from
Where is the commonest site

How do they present

A

Ventricles - can occur anywhere within the neuraxis, and most commonly in the spine.
Most common intracranial site is the posterior fossa

Commonly cause obstruction, so tend to present with hydrocephalus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How are ependymomas graded

A

G1 - subependymomas or myxopapillary ependymomas
G2 - cellular, papillary, clear cell and tanycytic
G3 - anaplastic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the investigations for an ependymoma

A

MRI brain and whole spine
MRI post op for extent of resection
CSF 14 days post op to exclude circulating tumour cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How is an ependymoma treated, and what determines adjuvant tx

A

surgery - resection of primary and mets

adjuvant tx if incompletely resected

if completely resected:
G1 - surveillance only
Gr2 - consider adjuvant tx
Gr3 - RT (adults = involved field only, children = whole CSA)

disseminated - CSRT with boost to all disease sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How is the radio sensitivity of germinomas

Where in the CNS do they tend to occur

A

very radiosensitive

midline - pineal gland, suprasellar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What ix are required prior to starting treatment for a germ cell tumour

A

Ophthalmological assessment
Audiogram
GFR for patients due chemotherapy
Endocrine assessment as indicated
Fertility preservation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How is the management of germ cell tumour categorised?

A

Non-secreting germ cell tumour
NS-GCT - 80% secreting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

For a non-secreting germ cell tumour, how is treatment divided

A

Localised
Metastatic

42
Q

What is the treatment for a non-secreting localised germ cell tumour

A

Localised - 4x PIE chemotherapy (cisplatin, ifosfamide, etoposide), followed by CSRT
40Gy/25#overall, 24Gy/15# to CSA with 16Gy/10# boost to primary site

43
Q

What is the treatment for a non-secreting metastatic germ cell tumour

A

No chemo
24Gy/15# CSA + tumour site boosts

44
Q

For a secreting germ cell tumour, how is treatment divided

A

Localised
Metastatic

45
Q

What is the treatment for a secreting localised germ cell tumour

A

4 x PIE (neo-adjuvant)
RT - 54Gy in 30# to primary (consider surgery for residual disease)

46
Q

What is the treatment for a secreting metastatic germ cell tumour

A

Phase 1 CSA - 30Gy in 20#
Phase 2 boost - brain sites - 24Gy in 15#; spinal sites - 16Gy in 10#

47
Q

Where do medulloblastomas tend to occur
How do they tend to present

A

Posterior fossa - midline for children, more likely lateralised for adults

Tend to present with symptoms of obstruction / raised ICP, or cerebellar symptoms

48
Q

What are the four subtypes of medulloblastoma

A

WNT, SHH, Group 3, Group 4

49
Q

How are medulloblastomas investigated / worked up

A

1/3 metastasise through the CNS, so pts need a spinal MRI and LP pre-operatively, or 14 days post op, to exclude circulating tumour cells

50
Q

What investigations are done post-op

A

MRI for possible residual disease
If resectable, further surgeries are done for the most complete resection possible

51
Q

How are medulloblastomas pts categorised post operatively

A

Standard or high risk

Standard risk
>3yrs age
<1.5 cm residual disease
CSF cytology negative
M0 (no metastases) on spinal staging
WNT and SHH groups

High risk
>1.5cm residual disease
CSF cytology positive (LP)
Metastases on staging imaging
Group 3 or 4 histology

52
Q

What adjuvant treatment is given for medulloblastoma

A

CSA RT followed by chemotherapy

53
Q

How is the CSA dose for medulloblastoma split

What adjuvant treatment is given following RT

A

High risk: 36Gy/20# to whole CSA followed by 18Gy/10# boost to primary site, with vincristine

Standard risk: 23.4Gy/13#, followed by primary site boost of 30.6Gy/17#, with vincristine

Overall primary tumour receives 54Gy/30#, with standard risk receiving less to the CSA

Following RT, adjuvant chemo is given
High risk - 8x PACKER chemotherapy
Lomustine, cisplatin, vincristine

Standard risk - modified PNET5 regime
Alternating cycles x8 of platinum/vincristine/lomustine, and cyclophosphamide

54
Q

What is the prognosis of treated medulloblastoma

A

5YS approx 80%
10YS 60%

55
Q

When is CSA RT indicated, and to what dose

A

All primitive neuroectodermal tumours (PNET):
Medulloblastoma - 54Gy/30# overall, according to risk
Supratentorial PNET
Pineoblastoma

Germ cell tumours:
Germinoma

Disseminated pilocytic astrocytoma

Ependymoma:
Gr3 adjuvantly for limited disease, or disseminated

56
Q

What is the RT dose to the pituitary
What is the CTV, and margins

A

Primary RT: 45Gy/25# or 54Gy/30# if functioning

Adjuvant RT for macroscopic residual disease: 50.4Gy/28#

GTV = residual disease, and reconstructed pre-op disease
CTV = GTV +5mm, and whole pituitary fossa
PTV = CTV +3mm

57
Q

How do low grade gliomas appear on MRI

A

T1 - typically hypo intense and do not take up contrast
T2 - Tumour is hyperintense, but no oedema
Hyperintense on FLAIR

58
Q

How do high grade gliomas appear on MRI

A

Hyper-intense on T1, take up contrast

59
Q

How does a pilocytic astrocytoma typically present

A

Most commonly occurs in children/TYA, and cerebellum, presenting with obstructive sx

60
Q

How is a pilocytic astrocytoma treated

A

Localised
Tx: Surgery

Disseminated
Rare, usually arise in cerebellum, hypothalamic region, optic chiasm, near brainstem

Tx: Craniospinal RT
To start within 4 weeks of diagnosis
Ph1 - CSRT - 24Gy/12# over 4 weeks (1.8Gy/#)
Brain boost to tumour bed - 18Gy in 10# over 2 weeks
+/- SC boost to disease sites - 14.4Gy in 10# over 2 weeks

GTV - All visible enhancing tumour on T1W + gad
CTV - GTV + 5mm, and include all meningeal reflections throughout CSA
PTV - CTV + 5mm (but CTV-PTV margin depends on site within CSA - larger margins lower down the spine)

61
Q

When should temozolamide and co-trimoxazole be held for deranged LFTs

A

ALT >148, ALP >325, bili >32 - hold co-trimox and tmp, until LFTs improved
ALT >245 / ALP >650 / Bilirubin >63 - discontinue both and continue RT alone

62
Q

How does a craniopharyngioma typically present

A

Visual defect: lower quadrantanopia (tumour pushes down from above)
Hormone deficiency & Raised prolactin due to compression of pituitary stalk
Headaches
Obstructive hydrocephalus
Diabetes insipidus - loss of ADH

63
Q

How is a craniopharyngioma treated

A

Surgery if possible
Primary RT if inoperable , or incomplete resection / recurrence.

RT 75-90% effective for local control

Dose:
Adjuvant - 50Gy/30#
Primary dose - 54Gy/30#

GTV-CTV: 5mm
Need to include all areas contacted by the tumour in the CTV

CTV-PTV: 3mm”

64
Q

When is RT indicated for an ependymoma

And at what dose

How is metastatic ependymoma treated

A

Indications:
Incomplete resection if pt >3 yrs old.
G3 tumours or high risk grade 2
Relapsed disease if no previous RT

Adjuvant:
Intracranial - 54Gy in 30# (protons for children)
Spinal cord - 50-55Gy in 30-33#
Cauda equina - 54Gy in 30# - 59.4Gy in 33#

Metastatic:
CSRT -> 36Gy in 20# to CSA & Boost to individual sites of spinal disease up to 50.4Gy

If there is positive cytology and no gross visible disease outside the primary location, give craniospinal fields 45Gy/25# over 5 weeks followed by boost of 14.4Gy/8#”

65
Q

What is the grading of ependymoma

A

G1-3

66
Q

What proportion of pituitary macro adenomas are non-secreting

A

25%

67
Q

What CNs are affected for a cavernous sinus tumour

A

III, IV, Va, Vb, VI

68
Q

What are the treatment options for a pituitary tumour

A

If non-secreting and no threat to vision - observation

If secretary and threat to vision:
Medical - cabergoline/bromocriptin/lanreotide
Surgical - indicated if threat to vision or failure of medical mx
Surgical approach is typically trans-sphenoidal, but can be transcranial if there is superior extension

RT: failure of medical mx but not fit for surgery, recurrence or residual disease, or persistent hormone secretion

69
Q

What is the outcome of surgery + RT to a pituitary tumour

A

80% relapse free survival at 20 years

70
Q

What is the rate of optic neuropathy for pituitary RT

A

1%

71
Q

How would a VS typically present

A

Unilateral sensorineural hearing loss
Balance problems
Involvement of the trigeminal nerve - facial pain or altered sensation

May expand into posterior fossa to occupy cerebellopontine angle -> compression of CN V, VII, VIII

72
Q

What is the treatment for a VS

A

Only 50% grow - monitor for serial growth
Surgery for young pts and large / cystic tumours
RT - SRS 12Gy/1# or 50Gy/30# fractionated

73
Q

What margin is used for VS SRS & fractionated

A

SRS:
GTV-CTV = 0mm
CTV - PTV=1mm

Fractionated:
GTV = CTV = visible tumour
CTV-PTV = 3mm

74
Q

where are the typical sites of chordoma
What marker is sent
What is the complication

A

Spheno-occipital
Sacral spine

Brachyury

Chordomas tend not to metastasise but can be locally invasive and have a high rate of recurrence

75
Q

What is the management of a skull base chordoma

A

Surgery and adjuvant RT, typically protons given location at the skull base
Chordomas receive 70Gy, chondrosarcomas 72Gy

CTV:
Clival lesion - GTV + entire clivus / sphenoid bone
Vertebral lesion - GTV + entire vertebral body

PTV:
CTV +3mm for skull base, 7mm elsewhere

76
Q

Where do paragangliomas tend to occur

What investigation is needed before treatment

What mutation is associated

A

Paravertebral - tend to be chromatin positive and release catecholamines
In relation to the great vessels of the head and neck eg carotid bodies - tend to be chromatin negative and don’t release catecholamines

Need MRI brain and whole spine to exclude phaeochromocytoma

10% are associated with SDH-mutation

77
Q

What is a glomus jugulare tumour

A

Paraganglioma arising from jugular foramen
Affect CN IX, X and XI

78
Q

How are meningiomas classified

A

Gr1-3

79
Q

How is a meningioma resection classified

A

Simpson classification

Stage 1 - Complete excision including dura and bone (tumour + dura + bone)
Stage 2 - Complete excision with co-angulation of dural attachment (tumour + dura)
Stage 3 - Excision of intradural tumour, without resection of it’s dural attachment (tumour alone)
Stage 4 - Partial removal, leaving intradural tumour in-situ
Stage 5 - Decompression only +/- biopsy

80
Q

What are the indications for RT for a meningioma

A

Primary RT:
Option for Grade 1
Inoperable
Recurrence

Adjuvant RT:
Incomplete resection
Grade 3
Atypical histology

81
Q

What RT dose is given to meningioma

A

SRS - 12-15Gy/1#

Fractionated:
G1 - 50Gy/30#
G2 - 55Gy/33# if Grade 2
G3 or sarcomatoid - 60Gy in 30#

82
Q

What dose is given to an optic nerve sheath meningioma

A

54Gy in 30#

83
Q

What are the RT volumes for a meningioma

A

Residual disease
GTV - Residual meningioma, hyperostotic bone and dural extension
CTV - GTV +1cm in plane of dura
If brain invasion present -> add 1cm into brain from brain/meningioma margin
Include all abnormal, hyperostotic bone not in GTV
PTV - CTV + 3mm

No residual disease
GTV - Pre-op MRI -> define largest extent of dural/bone thickening
CTV - GTV + 1cm in plane of dura, if documented brain invasion add 1cm into brain
Include all abnormal, hyperostotic bone
PTV - CTV + 3mm

84
Q

What is the treatment algorithm for a low grade glioma

A

Maximal surgery +/- RT (50.4Gy/30#) & 6x PCV

85
Q

What are the indications for upfront RT & ChT for a low grade glioma

A

Large initial tumour, >4cm
Incomplete resection / residual disease
>40yrs
New or worsening neurological deficit

86
Q

Does vincristine need dose adjustment for renal or hepatic impairment

A

No renal dose adjustment
Adjusted for hepatic impairment if bili >51 or ALT/AST >60

87
Q

What is the prognosis of a Gr3 oligo

A

5-yr OS: 30-35%
mOS 42mths with RT and PCV (oligo)

88
Q

What is the prognosis of a Gr3 astro IDH mut

A

60-100mths

89
Q

What is the prognosis of a Gr4 astro IDH mut

A

36mths

90
Q

What is the prognosis of a GBM IDH WT, mgmt methylated

A

20mths

91
Q

What is the prognosis of a GBM IDH WT, mgmt unmethylated

A

12mths

92
Q

What is the prognosis of a Gr1 tumour

A

Curable
80% 10yr survival

93
Q

What is the prognosis of a Gr2 tumour

A

med survival 5-10yrs
Buckner - mOS 13.3yrs with RT & PCV

94
Q

What is the prognosis of a Gr4 tumour

A

Stupp trial (age <70yrs) - mOS 14.6 for GBM with tx
2yr OS 26%
Pts with complete resection did better, and methylated MGMT vs unmethylated

95
Q

What is the prognosis of a GBM if age >70

A

Perry 2017 - 9.3mths with treatment (up to 12 cycles adj tmz) for all comers
If methylated - mOS 13.5mths
Most benefit in those with MGMT methylation. No statistically significant benefit for tmz if unmethylated

96
Q

How is a pineoblastoma treated

A

NA vinc/carbo/etopo x3-4 (treat like neuroendocrine)
CSA RT

97
Q

what factors should be considered when considering RT treatment of brain mets

A

Controlled or treatable extracranial disease
PS 0-1 (KPS ≥70)
Prognosis of at least 6mths

98
Q

When should fractionated intracranial RT be considered over SRS
What dose is typically used for fractionated RT

A

Lesions larger 2-3cm, lesions close to a critical OAR or where V12Gy ≥10cm3 (the volume of normal tissue, excluding GTV, that receives at least 12Gy)

V12Gy of 5, 10 and >15cm3 = risk of radio necrosis of 10%, 15% and 20%

27Gy/3# or 30Gy/5#

99
Q

What is the commonest primary brain tumour in adults

A

meningiomas, followed closely by astrocytomas

100
Q

What is the commonest malignant brain tumour in adults

A

glioblastoma multiforme.

101
Q

What is the commonest brain tumour and malignant brain tumour in children

A

low grade pilocytic astrocytomas
commonest malignant primary brain tumours -medulloblastomas