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CNS Flashcards

1
Q

What spinal level is end of cord?

A

L1/L2

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2
Q

What level is the end of the cord in children?

A

L3/L4

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3
Q

Spinal level of termination of thecal sac

A

S2

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4
Q

Describe the flow of CSF

A
  • Lateral ventricle
  • Foramen of munro
  • 3rd ventricle
  • Aqueduct of Silvius
  • 4th ventricle
  • Foramen of Luschka (lateral) and foramen of magendie (medial)
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5
Q

What are the contents of the cavernous sinus?

A
  • Cranial nerve III, IV, V1, V2, VI
  • Internal carotid artery
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6
Q

Which is the first CN usually damaged with cavernous sinus problem

A

CN VI

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7
Q

What CNS tumors associated with NF1?

A

Optic glioma

astrocytoma

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8
Q

What CNS tumors associated with NF2

A

Schwannomas

Meningioma

Astrocytoma

Ependymoma

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9
Q

What are the path hallmarks of glioblastoma

A

Nuclear atypia

Mitotic index

Endothelial proliferation

Necrosis

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10
Q

What is the spectroscopy signal of tumor

A

Increased choline

Decreased creatine and NAA

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11
Q

What is the spectroscopy signal of necrosis

A

Decreased choline

Increased lactate

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12
Q

How to make diagnosis of molecular GBM?

A
  • Histologic grade II or III astrocytoma
  • IDH wt
  • One or more of the following features
    • EGFR amplification
    • +7/-10 whole chromoscome gain/loss
    • TERT promoter mutation
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13
Q

What is first step for suspected HGG

A

Steroids if symptomatic

Maximally safe resection

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14
Q

What to look for on path report for HGG

A
  • MGMT methylation status
  • IDH status
  • EGFR amplification
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15
Q

When should CRT start after surgery for glioblastoma

A

4-6 weeks

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16
Q

What is the recommended treatment for glioblastoma (non elderly)

A
  • Maximally safe resection
  • RT to 60 Gy with concurrent and adjuvant temodar
  • Can discuss adjuvant TTF with patient which had improved OS
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17
Q

Dose of TMZ for concurrent CRT

A

75 mg/m2 daily (7d per week)

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18
Q

Dose of TMZ adjuvant

A

150 mg/m2 (cycle 1)

200 mg/m2 (cycle 2-6)

Dosed first 5 days of month for 28d cycles

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19
Q

How long does TTF have to be worn?

A

18+ hours a day

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20
Q

What is the algorithm for elderly GBM

A
  • High KPS: Stupp
  • Normal KPS: 40/15 with TMZ
  • Borderline
    • TMZ alone if methylated
    • RT alone if unmethylated
      • 40/15
      • 25/5
  • Low
    • Bev alone (if symptomatic)
    • Best supportive care
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21
Q

Best treatment for recurrent GBM

A

Enroll on clinical trial

Consider re-resection

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22
Q

Dose of bev for glioblastoma

A

10 mg/kg q2w

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23
Q

What is the best reRT dose

A

Enroll on trial

If off trial, 3.5 Gy x 10 to the contrast enhancement + 5 mm margin with bev if possible

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24
Q

What is median OS for glioblastoma with Stupp

A

15 months

23 months if MGMT methylated

12 months if unmethylated

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25
Q

What is highest tox of TMZ?

A

heme tox (7%)

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26
Q

What is the definition of elderly for glioblastoma?

A

Roa: 60

Perry (w TMZ): 65

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27
Q

What was the OS difference from TTF?

A

5 months

(21 months vs. 16 mos)

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28
Q

GBM volumes for Stupp

A

Fuse T1 post MRI and FLAIR

Contour T1post enhancing disease

Expand by 1.5 cm, adjust to cover all FLAIR+ disease and adjust off critical structures and natural anatomic boundaries

PTV margin of 0.5

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29
Q

Coverage target for HGG

A

>95% PTV receives 100% of dose

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30
Q

What hotspot is acceptable for HGG

A

<107%

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31
Q

Spinal cord tolerance

A

<50 Gy

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32
Q

Brainstem tolerance (conventional fx)

A

<55 Gy

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33
Q

Optic chiasm/nerve constraints (conventional)

A

<54 Gy

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34
Q

Retina constraint (conventional fractionation)

A

<45 Gy

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35
Q

Lens constraint (conventional fractionation)

A

Mean <7 Gy

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36
Q

Target coverage for hypofractionated glioblastoma

A

Heterogeneity within 5% (hotspot < 105%, cold spot > 95%)

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37
Q

OAR constraints for hypofractionated glioblastoma

A

Brainstem, optics, eye, retina

All should not receive more than 100% of Rx’d dose

Lens mean <4 Gy

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38
Q

What is expected OS for TMZ alone for glioblastoma

A

8 months

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39
Q

What is expected OS for RT alone for glioblastoma

A

5 months

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40
Q

What is the median survival after reRT and bev?

A

10 months

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41
Q

How often does progression occur on first post RT scan?

A

50%

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42
Q

Of the patients who progress early, how many are true POD?

A

50%

DO NOT CHANGE MGMT AFTER FIRST SCAN

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43
Q

For anaplastics, what should be asked about path report?

A
  • Path - oligo or astrocytoma
  • IDH status (trumps all)
  • 1p19q codel status
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44
Q

What is IDH?

A

enzyme in Krebs cycle

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45
Q

What is PCV?

A
  • Procarbazine
  • CCNU (lomustine)
  • Vincristine
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46
Q

How is PCV administered?

A

Procarbazine and Lomustine are oral

Vincristine is IV

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47
Q

How long is a cycle of PCV?

A

6 weeks

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48
Q

What is the pCV schedule?

A

Day 1- vincristine and lomustine

D1-10: procarbazine

32 days off

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49
Q

What percentage of anaplastic gliomas are enhancing?

A

2/3

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50
Q

How should anaplastic gliomas be classified

A
  • If IDHwt –> molecular glioblastoma
  • If IDHmut
    • 1p19q codel –> molecular oligo
    • 1p19q intact –> molecular astro
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51
Q

How to approach IDHwt anaplastic gliomas?

A

Would treat like glioblastoma (on protocol)

60 Gy in 30 fractions with concurrent adjuvant TMZ

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52
Q

How to treat IDHmt anaplastic gliomas?

A
  • Maximal safe resection
  • If 1p19q codel –> RT to 59.4 Gy –> adjuvant PCV x 6 cycles
  • If 1p19q non-codel –> RT to 59.4 –> adjuvant TMZ
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53
Q

What is the RT dose for anaplastic gliomas

A

59.4 Gy in 33 fractions of 1.8 Gy

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54
Q

How should chemo be given for anaplastic astro?

A

If IDHwt –> concurrent/adjuvant

If IDHmt –> adjuvant only (per CATNON)

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55
Q

What is the expansion for anaplastic gliomas

A

Cavity + 1.5 cm, include FLAIR

0.5 cm PTV margins

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56
Q

What is expected OS for anaplastic oligo?

A

14 years

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57
Q

What is expected survival for anaplastic astro, IDH mt

A

6 years

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58
Q

What are the path characteristics of pilocytic astrocytoma

A

Rosenthal fibers

Located in cerebellum or 3rd ventricle

Generally pts < 25 years old

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59
Q

What LGG patients are considered high risk?

A

Age > 40

STR

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60
Q

What are the negative prognostic features of LGG per EORTC

A

SATAN

  • Size > 6 cm
  • Age > 40
  • Tumor crossing midline
  • Astrocytic component (1p19q intact)
  • Neuro deficits preop (including seizures)
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61
Q

Approach for high risk LGG

A
  • Maximal safe resection
  • RT to 54 Gy in 30 fractions
    • If 1p19q codel –> adjuvant PCV x 6 cycles
    • If IDH mt but 1p19q intact –> adjuvant TMZ
    • If IDH wt –> consider concurrent and adjuvant TMZ
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62
Q

Approach to low risk LGG

A

Maximal safe resection –> observation

Reminder: age <40, GTR

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63
Q

Approach to pilocytic astro

A

Maximally safe surgery

RT only if recurrence or biopsy

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64
Q

RT dose for pilocytic astro

A

1.8 x 28 = 50.4 Gy

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65
Q

Contouring for LGG

A

Contour FLAIR on MRI

CTV = 1 cm expansion, respect boundaries

PTV = 0.5 cm

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66
Q

What is 10 year OS for grade II oligo

A

75%

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67
Q

What is 10 year OS for grade II astro

A

45%

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68
Q

What percentage of the grade II tumors undergo malignant transformation?

A

50%

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69
Q

Does RT increase rate of malignant transformation for LGG?

A

No

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70
Q

What is the radiographic appearance of PCNSL

A

Homogeneous, multifocal

Periventricular

Crossing corpus callosum

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71
Q

What stage is PCNSL

A

Ann Arbor IE

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72
Q

What is the workup for PCNSL

A

Do not start steroids

MRI brain
MRI spine
PET CT

Testicular US for men >60

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73
Q

Other workup needed for PCNSL

A
  • LP
  • Eye exam
  • Brain biopsy if LP non diagnostic
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74
Q

Necessary labwork for PCNSL

A
  • CBC
  • CMP
  • LDH
  • EBV
  • HIV
  • Toxo
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75
Q

How to approach if bx negative on steroids

A

Hold steroids

Re-biopsy on progressions

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76
Q

Treatment approach for fit patients with PCNSL

A
  • R-MVP x 5 cycles
    • If CR –> reduced dose WBRT –> 2 cycles Ara-C
    • If PR –> 2 more cycles RMVP
      • If CR after 7 cycles –> rdWBRT
      • If PR after 7 cycles –> 45 Gy WBRT
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77
Q

What is R-MVP

A

Rituximab

High dose MTX

Vincristine

Procarbazine

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78
Q

How often is a cycle of RMVP

A

q2w

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79
Q

What is the dose of MTX for PCNSL

A

3.5 mg/m2

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80
Q

What should be treated for PCNSL

A

WBRT

Include posterior 1/3 of orbit (bb at lateral canthus with half beam block)

Cover to C2/C3

If ocular involvement, include bilateral orbits

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81
Q

Dose of WBRT for PCNSL

A

If CR to RMVP = 23.4 (1.8 x 13)

If PR to RMVP = 45 (1.8 x 25)

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82
Q

What is a low risk meningioma?

A

New grade 1 (any extent of surgery)

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83
Q

What is an intermediate risk meningioma?

A
  • Recurrent grade I
  • Grade II with GTR
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84
Q

High risk meningioma

A
  • Recurrent grade 2
  • New grade 2 s/p STR resection
  • New or recurrent grade 3 (any extent of surgery)
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85
Q

Recommended treatment for low risk meningioma

A

Surgery –> observation

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86
Q

Recommended treatment for intermediate risk meningioma

A

Surgery –> 54 Gy

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87
Q

Recommended treatment for high risk meningioma

A

Surgery –> 54 Gy with boost to 60 Gy to high risk region

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88
Q

How many meningiomas have a dural tail?

A

2/3

89
Q

What is the path hallmark of meningiomas

A

psamomma bodies

90
Q

How many mitoses for WHO grade I meningioma

A

<4 per HPF

91
Q

How many mitoses for grade II meningioma

A

4-19 mitoses

evidence of brain invasion

clear cell or choroid histology

92
Q

Number of mitoses for grade III meningioma

A

20+ mitoses

rhabdoid histology

93
Q

Which Simspon grades designate GTR?

A

I-III

94
Q

What is Simpson grade IV resection

A

STR, 40% chance of symptomatic recurrence

95
Q

What is Simpson grade V resection

A

Biopsy only

96
Q

What is the recommended initial treatment for meningioma?

A

Get old scans, if first scan, consider obs if asymptomatic and small (<3 cm)

Get new scan in 6 months

97
Q

Fractionated RT dose for grade I meningioma

A

54 Gy in 30 fractions

98
Q

Fractionated dose to grade II meningioma

A

If adjuvant after GTR = 54 Gy in 30 fx

If recurrent or STR = 54/60 in 30 fx

99
Q

Fractionated RT dose for grade III meningioma

A

54/60 Gy in 30 fractions

100
Q

SRS dose for meningioma

A

15 Gy x 1

only for grade I

101
Q

What is max size for SRS for meningioma

A

3.5 cm

102
Q

What is the SRS chiasm constraint

A

8 Gy MPD

103
Q

How to do CTV for intermediate risk meningioma

A
  • Contour postop bed and any gross residual
  • Form CTV54 by doing 1 cm expansion
  • Shrink CTV to 5 mm along natural boundaries including bone and brain if no involvement
  • 5 mm PTV expansion
104
Q

What is contouring for high risk meningioma

A
  • Contour postop cavity and any residual enhancing disease
  • Create CTV54
    • Expand by 2 cm (reducing to 1 cm in natural boundaries)
    • Treat to 54 Gy
  • Create CTV60 using SIB
    • Expand cavity+residual by 1 cm
    • Treat to 60/30 Gy
  • Do 5 mm expansion for both
105
Q

Bilateral acoustic neuromas is pathognomonic for

A

NF2

106
Q

What is the workup for an acoustic neuroma

A

Audiology

MRI IAC protocol

NF2 testing if bilateral

Clinical diagnosis but should see skull base surgeon

107
Q

What is the scale for servicable hearing

A

Gardner-Robertson

108
Q

What is the scale for facial nerve function

A

House-Brackman

109
Q

What type of hearing loss is typically associated with acoustic neuroma

A

high frequency

110
Q

What is management strategy for acoustic neuroma?

A

If asymptomatic, small, first scan –> consider observation

Other options include surgery, EBRT or SRS

111
Q

What is the LC for acoustic neuroma with EBRT vs SRS

A

Both excellent, >90%

112
Q

What is the hearing preservation rate with RT

A

~70%

113
Q

How quickly do acoustics usually grow?

A

2 mm per year

114
Q

If treating acoustic with conventional fractionation, what is the dose?

A

50.4 Gy in 28 Gy fractions

115
Q

What is the contouring strategy for acoustic neuroma

A
  • Contour GTV
  • No CTV
  • If EBRT –> 3 mm margins
  • If SRS –> 1 mm margins
116
Q

What dose for SRS for acoustic neuroma?

A

12.5 Gy x 1

117
Q

What is needed to ensure SRS is done safely

A

AlignRT, facial surface recognition

118
Q

What dose level is SRS planned to?

A

80% IDL (20% hotspot)

119
Q

Which lesions might benefit from EBRT for acoustics?

A

Larger lesions

Very symptomatic

Lesions abutting brainstem or edema

120
Q

What is the dose constraint for acoustic neruoma

A

Brainstem < 12 Gy

Cochlea mean < 4 Gy (this is not possible)

121
Q

What is the rate of CN VII or CN V damage from RT for acoustic neuroma

A

<10%

122
Q

What share of acoustics enlarge after RT?

A

30%

123
Q

Differential diagnosis for sellar/suprasellar mass

A
  • Pituitary adenoma/carcinoma
  • Craniopharyngioma
  • Germinoma
  • Optic glioma
  • Meningioma
  • Abscess
  • Mets
124
Q

What is inferior to sella?

A

sphenoid sinus

125
Q

What is lateral to sella turcica?

A

cavernous sinus

126
Q

What is in cavernous sinus

A

CN III, IV, V1, V2, VI

ICA

127
Q

What hormones produced by posterior lobe of pituitary

A

ADH

Oxytocin

128
Q

What is size definition of macroadenoma

A

>1 cm

129
Q

What are the symptoms of hyperprolactinemia

A

Galactorrhea

Amenorrhea

Decreased libido

Infertility

130
Q

What is workup for pit tumor

A

Endo evaluation

Visual loss

CN exam

Optho consult for visual field testing

131
Q

What is the classic ocular finding for pit tumor?

A

Bitemporal hemianopsia

132
Q

What labwork should be sent/

A

Prolactin

GH or IGF-1

ACTH/Cortisol

TSH

FSH/LH

133
Q

What is the prolactin level most likely a prolactinoma?

A

>20 suspicious

>200 very likely

134
Q

What imaging to get for pituitary tumor

A

MRI brain with thin cuts through sella

Residual tumor can enhance with gad

135
Q

What is the general treatment approach for pit tumors

A
  • If asymptomatic and non-functional –> observation
  • If prolactinoma –> medical management first
  • If other secreting –> TSS
  • If inoperable –> definitive RT
136
Q

If patient has TSS which is STR what is next step

A

Generally Observe and give RT for recurrence

137
Q

How to approach prolactinoma?

A
  • Start with medical management even if visual symptoms
  • Cabergoline 0.25 mg twice a week
  • TSS if failure of medical mgmt
138
Q

Role of RT for prolactinoma

A

Failed medical management and inoperable

Failed med management –> TSS –> persistent disease

139
Q

How to approach functional pituitary tumors

A
  • Push for surgery
    • Can observe STR if asymptomatic and not near critical structures
    • Adjuvant RT (6 weeks postop) if persistence of hormone secretion or STR
    • All TSH-secreting tumors need postop RT
140
Q

If you have a functional tumor, when should medicines be started

A

BEFORE surgery

141
Q

If meds given preop for TSS, when should they be stopped

A

After surgery, before RT

142
Q

Which functional tumor requires postop RT

A

TSH-secreting

54 Gy

143
Q

How much space is required between tumor and chiasm to use SRS

A

At least 3 mm

144
Q

In order to use SRS for pit tumors must respect what constraints?

A

Optics < 8 Gy

Brainstem < 12 Gy

145
Q

Contouring pituitary tumor

A

GTV + 5 mm for EBRT

GTV + 3 mm for SRS

146
Q

RT dose for non-functional pituitary adenoma

A

If EBRT - 45 Gy in 1.8 fx

If SRS - 14 Gy x 1

147
Q

RT dose for functional pituitary adenomas

A

If TSH secreting - 54 Gy

If others - 50.4 Gy in 1.8 Gy

If SRS - 20 Gy x 1

148
Q

What is cochlea constraint - SRS

A

Mean <4 Gy

149
Q

What is LC of pit tumors after RT

A

90%

150
Q

What is rate of hormone normalization after surgery for pit adenoma

A

50-80%

151
Q

Rate of hormone normalization after pituitary RT

A

30-50%

Can take 12-18 months

152
Q

How many pit patients become hypopit after RT

A

50%

153
Q

Which hormone is first to be lost after pituitary RT

A

GH (generally 3-5 years later)

154
Q

How to manage DI?

A

Desmopressin

155
Q

Why does DI occur from pit tumor

A

Damage to posterior pituitary, loss of ADH

156
Q

For AVM, what is the workup

A

MRI and MRA

CT angio or IR angio

157
Q

How to approach an AVM?

A
  • If unuptured –> observation
  • If previous rupture options include
    • Microsurgery
    • SRS
    • Embolization
158
Q

What is the risk of hemorrhage with unruptured AVM?

A

2% per year

159
Q

What is the recommended SRS dose for AVM?

A

If <3 cm: 20 Gy to 50% IDL

If >3 cm: 16 Gy to 50% IDL

160
Q

How to approach if AVM is larger than 3 cm?

A

Consider staged procedures, 2 sessions 6 months apart

161
Q

What is the target for AVM SES?

A

nidus of AVM, not feeding vessels

162
Q

For SRS what is the V12 goal

A

<10 cc

163
Q

What is success rate of AVM obliteration with SRS

A

80-90%

Over 1-3 years

164
Q

SRS dose for trigeminal neuralgia

A

80 Gy to 100% IDL

165
Q

What is treatment for chordoma?

A

Maximally safe resection –> RT (protons if possible)

166
Q

Dose of RT for chordoma

A

If resected R0 –> 60 Gy

If R1: 70 Gy

If R2: >70 Gy

167
Q

Management of spinal ependymoma

A
  • Maximally safe resection
    • If GTR and grade 1/2 –> observation
    • If STR –> adjuvant RT
168
Q

Dose of RT for spinal ependymoma

A

50.4 in 28 daily fractions of 1.8 Gy

169
Q

SRS Brainstem Max - 1 FX

A

12 Gy

170
Q

SRS max to optic chiasm and optic nerves

A

8 Gy

171
Q

Cochlea constraint for SRS

A

Mean < 6 Gy

MPD < 12 Gy

172
Q

Goal V12 for SRS

A

<10cc

<20% risk of necrosis

173
Q

Goal brain dose for 3 fx SRS

A

V18 < 30 cc (3 fx)

174
Q

What is the SRS dose fall off

A

10% per mm

175
Q

What is our SRS prescribed to

A

80% IDL

Linac based

125% hotspot

176
Q

Brainstem - conventional

A

MPD of 54 Gy

D5% = 60 Gy if involved

177
Q

Optic chiasm constraint - conventional

A

54 GY

178
Q

Optic nerve constraint - conventional

A

54 Gy

179
Q

Cochlea constraint - conventional

A

Mean <45 Gy

180
Q

Retina constraint - conventional

A

MPD of 45 Gy

181
Q

Lens constraint - conventional

A

Mean < 7 Gy

182
Q

Spinal cord constraint - conventional

A

MPD < 45 Gy

183
Q

Hippocampal avoidance, dmax

A

16 Gy

184
Q

Hippocampal avoidance, mean dose

A

9 Gy

185
Q

Optics constraint 5 fx

A

5 x 5 MPD

186
Q

Optics constraint 3 fx

A

18 Gy in 3 fx

187
Q

Cochlea constraint - 3 fx

A

15 Gy / 3 fx MPD

188
Q

Cochlea constraint - 5 fx

A

25 / 5 MPD

189
Q

Brainstem constraint for 3 and 5 fx

A

allow D05% to be Rx dose (either 6x5 or 9x3)

190
Q

Spinal cord constraint 3 fx

A

D0.35cc getting 18 Gy in 3 fx

191
Q

Spinal cord constraint in 5 fractions

A

D0.35cc getting 23 Gy in 5 fx

192
Q

Cauda constraint - 3 fx

A

D5cc 22 Gy / 3 fx

193
Q

Cauda constraint 5 fx

A

D5cc - 30 Gy in 5 fx

194
Q

Risk of permanent alopecia at 60 Gy

A

70%

195
Q

How long until hair grows back after RT

A

2-3 months

196
Q

How long after RT do cavernous malformations occur

A

years

197
Q

Conformality index

A

Prescription isodose volume / tumor volume

198
Q

Ideal conformality index

A

1

(accept 1-2)

199
Q

Heterogeneity index

A

Max dose to tumor / prescribed dose

200
Q

Ideal heterogeneity index

A

<2

201
Q

Gradient index

A

Volume receiving 1/2 Rx dose / volume receiving 100% Rx dose

202
Q

Ideal gradient index

A

~3

203
Q

Steroid dose for BM

A

Loading dose of 10 mg

Standing dose of 4-6 q6 pending symptoms

204
Q

Dose of SRS for 21 Gy

A

<2 cm

205
Q

Options for leptomeningeal disease

A

Clinical trial

Intrathecal or systemic chemo options

WBRT + focal spinal RT for symptoms

206
Q

What is the advantage of WBRT + SRS

A

No OS benefit but decreases brain recurrence

207
Q

Memantine dosing

A

Check kidney function

Week 1: 5 mg

Week 2: 5 BID

Week 3: 10 / 5

Week 4: 10 BID

208
Q

Findings of hippocampal avoidance trial

A

Risk of cognitive failure was significantly lower after HA-WBRT plus memantine versus WBRT plus memantine

less deterioration in executive function at 4 months (23.3% v 40.4%; P = .01) and learning and memory at 6 months

209
Q

What sequence should be used to contour hippocampus

A

T1

210
Q

gray is gray on which sequence

A

T1

211
Q

How to generate hippocampal avoidance zone

A

Contour bilateral hippocampus

5 mm expansion to create avoidance zone

212
Q

What is PTV for HA-WBRT

A

whole brain parenchyma, excluding HA region

213
Q

What is the PTV margin on brain for HA-WBRT

A

0 mm

214
Q

What is the hippocampal volumetric constraint for HA-WBRT

A

D100% of <9 Gy

215
Q

MPD to hippocampus for HA-WBRT

A

<16 Gy

216
Q

What is the dose constraint to HA region

A

None, MPD and D100% is for hippocampus only

217
Q

Guidelines for contouring postop cavities

A

Include entire surgical cavity using T1 post MRI

Include entire surgical tract

If tumor touching dura, include 5-10 mm extension along bone flap beyond region touching

If not touching dura, generally margin of 5 mm along bone flap sufficient

218
Q
A

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