Chapter 84 CNS Tumors In Children Flashcards Preview

Perez and Brady's Principles and Practice of Radiation Oncology 6th Edition > Chapter 84 CNS Tumors In Children > Flashcards

Flashcards in Chapter 84 CNS Tumors In Children Deck (225)
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1
Q

What percentage of childhood malignancies known with genetic predisposition?

A

2-5%

2
Q

What are the genetic predisposition in childhood malignancies?

A
  1. Neurofibromatosis types 1(NF-1) and 2 (NF-2)
  2. Tuberous Sclerosis
  3. Nevoid basal cell(Gorlin’s) syndrome
  4. Familial adenomatous polyposis
  5. Li-Fraumeni syndrome
3
Q

What is the main predisposing factor of childhood malignancies?

A

Majority remains with no predisposing factors

4
Q

Radiotherapy causes disrupted neuro Genesis and cortical atrophy. Patient failed to acquire new knowledge and skills at age-appropriate rate and show progressive decline in IQ over time. The magnitude of deficit depends on?

A
  1. Age at treatment
  2. Tumor location
  3. Treatment factors(RT volume, dose and use of chemotherapy)
5
Q

What intervention could be used for helping patients with RT induced deficits?

A

The following can be start soon after treatment for best results

  1. Cognitive or behavioral therapy
  2. Pharmacotherapy
  3. Exercise
6
Q

Endocrine deficit are very common after RT. Which harmone deficiency is primarily responsible that correlates with dose of RT?

A

Growth harmone

7
Q

Which harmone deficiency is primarily responsible that is seen after CSI?

A

Thyroid harmone

8
Q

What percentage of CNS malignancies occurs in childhood?

A

20-25%

9
Q

What strategies could be used to avoid or minimize long term effects of treatment for pediatric brain tumor?

A
  1. Avoidance of RT altogether
  2. Delay of RT for age 3-8 years by chemotherapy
  3. Use of daily anesthesia, improved immobilization, daily pretreatment image verification
  4. Use of new RT modalities eg Proton
  5. Use of reduced RT target volume eg in medulloblastoma
  6. Reduce RT dose eg in medulloblastoma
  7. Use of small fraction size in radiosensitive tumor eg germinoma 1.5Gy/Fx
  8. HFRT eg current Europian studies in Medulloblastoma
10
Q

During patient positioning and immobilization in CSI, what maneuver will help avoid dentition in exit dose from superior aspect of spinal field?

A

Neck extension with careful selection of level for junction of brain and spinal fields

11
Q

Lower border of thecal sac can be as high as L5 and as low as S3. In the interest of CTV coverage and normal tissue sparing, how do we individualize lower border of spine field in CSI?

A

MRI findings

12
Q

During CSI, what percentage of variation of dose along spinal axis will require use of dose compensation and how can we achieve that?

A

> 10%

Using MLC

13
Q

What are possible solutions for field matching over cervical spine/risk of over- or under dosage?

A
  1. Angle brain fields
  2. Use half beam blocks for brain fields
  3. Use couch rotation or match line wedge
14
Q

What are possible solutions for irradiation of normal tissue thyroid gland?

A

Care of level of junction

15
Q

Most common CNS tumor in pediatric age group?

A

Medulloblastoma

16
Q

Most common CNS tumors in adult group?

A

High grade glioma

17
Q
WHO classification of Astrocytic tumors
Grade I
Grade II
Grade III
Grade IV
A
Grade I - Pilocytic Astrocytoma
      Pilomyxoid Astrocytoma - aggressive behavior, may include leptomeningeal seeding
Grade II - Diffuse Astrocytoma
      Fibrillary Astrocytoma
      Gemistocytic Astrocytoma
      Protoplasmic Astrocytoma
Grade III - Anaplastic Astrocytoma
Grade IV - Glioblastoma Multiforme
      Giant Cell Glioblastoma
       Gliosarcoma
Subependymal Giant Cell Astrocytoma - Rare
Pleomorphic Xanthoastrocytoma - Rare
Gliomatosis cerebri
18
Q

What are low grade glioma?

What is the overall survival rates at 10 and 15 years

A

Grade I/II

80-100%

19
Q

Group LGGs according to an anatomic locations

A
Cerebellar Astrocytoma
Hemispheric Astrocytoma
Midline Supratentorial tumors
     Corpus Callosum
     Lateral and third ventricle
     Hypothalamus 
     Thalamus
Optic pathway tumors
Brainstem LGAs
LGAs of Spinal Cord
20
Q

What is most common Astrocytoma in pediatric age group?

A

Pilocytic Astrocytoma

21
Q

Name the sites accounting for almost all of LGAs, Pilocytic

A

Cerebellum

Anterior Optic Pathway

22
Q

Describe macroscopic features of Pilocytic Astrocytoma

A

Well circumscribed, associated cystic component.

23
Q

Describe microscopic features of Pilocytic Astrocytoma

A

Biphasic pattern

  1. Varying proportion of compacted bipolar cells with Rosenthal fibers
  2. Loosely textured multipolar cells with microcysts and granular bodies
24
Q

Features compatible with Pilocytic Astrocytoma but not a sign of malignancy

A

Rare mitosis
Occasional hyperchromatic nuclei
Micro vascular proliferation
Infiltration of meninges

25
Q

Large proportion of diffuse astrocytoma arise from?

A

Intrinsic pontine tumors

Cerebral hemisphere

26
Q

Describe macroscopic features of diffuse astrocytoma

A

Infiltration rather than destruction of anatomic structure

Usually not well circumscribed

27
Q

Describe microscopic features of diffuse astrocytoma

A
  1. Well differentiated fibrillary or gemistocytic neoplastic astrocytoma on a background of loosely structured often microcystic tumor matrix
  2. Presence of nuclear atypia is diagnostic criterion
  3. Mitotic activity, necrosis, microvascular proliferation are absent
28
Q

Symptoms relate to location of tumors

  1. Hemispheric tumor
  2. Hypothalamic tumor
  3. Diencephalic syndrome
A
  1. Focal motor deficit
  2. Neuro endocrine deficit
  3. Emaciation with loss of subcutaneous fat despite normal or increased appetite , alert appearance, increased vigor and euphoria, pallor without anemia, nystagmoid movement of eyes.
29
Q

Name LGAs who may not require any tumor specific treatment. Initial approach of surveillance with active intervention will be taken only at the time of progressive disease that is symptomatic

A
  1. NF-1 with optic pathway tumor

2. LGAs with tectal lesion with hydrocephalus without localizing brain stem signs.

30
Q

What percentage of complete resection is achieved in cerebral, cerebellar, spinal cord tumors?

What percentage of complete resection is achieved in diencephalic tumor?

A

> 80%

50%

31
Q

In joint CCG-POG study, subtotal resection without adjuvant treatment, what is 8 years progression free survival and overall survival rates?

A

PFS with 1.5 cm3 residual 45%

OS with 1.5cm3 residual 90%

32
Q

What is the role of post-operative radiotherapy in less than complete tumor resection?

A

It results in improved disease free survival without benefit in overall survival

33
Q

What is the period for risk of disease progression after incomplete tumor resection?

A

Initial 3 years after incomplete tumor resection

34
Q

When does second surgery be considered?

When does other treatment be reserved like RT and Chemotherapy?

A

At tumor progression and operable

At tumor progression and inoperable

35
Q

What is the indication of adjuvant chemotherapy particularly in infant and young children and patient of all ages with NF-1?

A

Patient are greatest risk of developing neuro cognitive, vaso-occlusive and neuroendocrine sequelae of RT treatment.

36
Q

What is the overall response rate in terms of stable disease to chemotherapy as adjuvant therapy in LGAs?

A

70-100%

37
Q

How long can chemotherapy permit delay of RT?

A

2 to 4+ years

38
Q

What age group benefit delay of RT by using chemotherapy?

A

5-8 years

39
Q

CTV margin for pilocytic astrocytoma?

A

0-1 cm around GTV in T1 weighted gadolinium enhanced images

40
Q

CTV margin for infiltrative diffuse fibrillary astrocytoma?

A

1-1.5 cm around GTV seen in T2 weighted or Flair images

41
Q

What is standard dose of LGAs?

A

50-54Gy

42
Q

What are radioactive solutions used in recurrent LGAs after RT where symptoms relate more to cyst wall than solid component of tumor?

A

32P
90Y
198Au
186Re

43
Q

Post RT MRI in initial months shows no change in tumor volume or rather increase in size..what should you do next?

A

Tumor regression in LGAs is slow..post RT imaging, tumor may remain stable or increase in size..close follow up with repeat imaging is best approach.

44
Q

What percentage of high grade astrocytoma accounts for all CNS tumors in pediatric age group?

A

5%

45
Q

What comprises of HGAs?

A

Grade III Anaplastic Astrocytoma(AA)

Grade IV GBM

46
Q

Describe 6 histopathologic features of HGAs

A
Nuclear atypia
Cellular pleomorphism
Mitotic activity
Vascular thrombosis
Microvascular proliferation
Necrosis
47
Q

HGAs is common in what age group?

A

Older adolescent

48
Q

What are the common sites of HGAs?

A

2/3 cerebral hemisphere

Remaining : deep midline structures thalamus, basal ganglia, cerebellum

49
Q

What is the predominant failure pattern in HGAs?

A

Local

50
Q

What is the percentage of leptomeningeal spread in HGAs?

A

10-30%

51
Q

Describe the basic principle of treatment in HGAs

A

Surgery followed by RT

Complete resection shows survival advantage
Maximal surgical resection compatible with good neurological outcome
Second surgical procedure if significant residual tumor after first

52
Q

Describe target delineation in HGAs

A

GTV of tumor bed, residual enhancing or non enhancing residual tumor plus abnormality seen in T2 weighted MRI with CTV margin of 1.5cm

53
Q

What is dose prescription in HGAs?

A

54-60 Gy standard dose

50-54Gy if dose tolerance of normal organ like optic chiasm exceeds its dose constrain

54
Q

What chemotherapy can be used in adult HGAs ?

A

Temozolamide

55
Q

What is median time of progression and overall survival at 5 years of HGAs in children

A

Median time of progression 10-11 months

Overall survival 20%

56
Q

In HGAs, by location which has good and bad prognosis?

A

Good prognosis cerebral hemisphere

Bad prognosis thalamic lesion

57
Q

In HGAs, by age which has good and bad prognosis?

A

Good prognosis younger than age 3

Bad prognosis older children more than 3 years

58
Q

p53 over expression and MIB-1 labeling index has good or bad prognosis?

A

Bad prognosis

59
Q

What is the age group of optic pathway glioma?

A

2-6 years

75% are younger than 10 years

60
Q

1/3rd of optic pathway glioma is associated with what genetic predisposing factor?

Bilateral optic nerve involvement is pathognomonic of?

A

NF-1

61
Q

Name 3 clinicopathologic entities of optic pathway glioma

A
  1. Tumor confined to optic nerve
  2. Anterior tumor : tumor confined to optic chiasm
  3. Posterior or chiasmatic/hypothalamic tumor(70%) : tumor involve hypothalamus or adjacent structure
62
Q

Describe general principle of treatment of optic pathway glioma

A

Surgical resection if no useful vision
Chemotherapy for infants and age up to 5 years if useful vision
Radiotherapy for older children

63
Q

What is the long term tumor control rate with chemotherapy or radiotherapy in optic pathway glioma?

A

100%

64
Q

Describe general principle of chiasmatic glioma

A
  1. Surgery is NO option
  2. NF-1 and younger than 5 years : Surveillance is appropriate initial management or Chemotherapy
  3. Without NF-1 and older children : radiotherapy is reserved for salvage after chemotherapy
65
Q

Long term progression free survival and overall survival in chiasmatic glioma

A

Long term progression free survival 60-90%

Overall survival 90-100%

66
Q

What are early and late findings of posterior or chiasmatic/hypothalamic glioma?

A

Early findings : nystagmus, impaired visual acuity, visual field defects

Late findings : increased head circumference, signs and symptoms of increased ICP

67
Q

Describe general principles of posterior or chiasmatic/hypothalamic glioma

A
  1. CSF diversion and surgical resection
  2. Chemotherapy NF-1 with younger than 5 years
  3. Radiotherapy without NF-1 with older children, disease progression with chemotherapy, disease progression at diagnosis or after surgery.
68
Q

What is dose prescription of posterior or chiasmatic/hypothalamic glioma

A

45-50 Gy younger children

50-54 Gy older children above 5 years

69
Q

What is the local tumor control with RT in posterior or chiasmatic/hypothalamic glioma?

A

70-80%

70
Q

What is the long term survival in posterior or chiasmatic/hypothalamic glioma?

A

50-80%

71
Q

Patient of posterior or chiasmatic/hypothalamic glioma with NF-1, how do we do follow up?

A

MR angiography as part of regular follow up imaging protocol and intervene surgically if necessary to avoid CVA

72
Q

Why do we need MR angiography for follow up of patient with posterior or chiasmatic/hypothalamic glioma?

A

With NF-1 they are at greatest risk of moyamoya syndrome, a progressive vasocclusive process involving circle of willis

73
Q

What percentage of brainstem glioma comprises of all CNS tumors in pediatric age group?

A

10-15%

74
Q

Name favorable groups of brainstem glioma

A

Low grade focal
Dorsal exophytic
Cervicomedullary tumors

75
Q

Name more aggressive brainstem glioma

A

Diffuse intrinsic pontine glioma

76
Q

Describe features of low grade focal brainstem glioma

A

Well circumscribed, cystic, without evidence of infiltration, without edema

77
Q

Describe general principle of treatment of low grade focal brainstem glioma

A

Surgery in experienced hands for well selected cases

Standard RT of 54Gy over 6 weeks with CTV margin of 0.5cm

78
Q

What are the factors that depends on outcome of conventional RT in low grade focal brainstem glioma?

A
  1. location - pons vs others
  2. Imaging appearance - tumor volume, density on CT, enhancement pattern)
  3. Histology - malignant vs benign
79
Q

Describe radiological findings of dorsal exophytic brainstem glioma

A

MRI sharply delineated from surrounding tissue
Hypointense on T1
Hyperintense on T2
Enhance uniformly and brightly after gadolinium

80
Q

What is most common histology of tumor in dorsal exophytic brainstem glioma

A

Pilocytic astrocytoma

81
Q

What is the treatment of choice for dorsal exophytic brainstem glioma

A

Surgery

82
Q

What is the indication of RT in dorsal exophytic brainstem glioma

A

Routine postoperative RT NOT indicated
Should be considered for
High grade lesion
Disease progression in early

83
Q

Treatment strategy for tumor recurrence in dorsal exophytic brainstem glioma

A

Further surgery and RT

84
Q

How is the overall prognosis of dorsal exophytic brainstem glioma

A

Excellent

85
Q

What is the treatment choice for cervicomedullary brainstem glioma

A

Surgery

86
Q

What is the gross total resection rate of cervicomedullary brainstem glioma

A

70-80%

87
Q

What is the indication of RT in cervicomedullary brainstem glioma?

A

NO indication of RT

88
Q

What is the common histology of tumor in diffuse intrinsic pontine brainstem glioma

A

Fibrillary Astrocytoma

89
Q

Name cranial nerves commonly involved in diffuse intrinsic pontine tumors

A

CN VI and VII

90
Q

Describe radiologic feature of diffuse intrinsic pontine brainstem glioma

A

Best seen in T2 or FLAIR

Ring enhancement suggestive of high grade histology

91
Q

What is the indication of surgery in diffuse intrinsic pontine brainstem glioma

A

Surgery has NO role

92
Q

What is the progression free survival, survival rate at 2 years in DIPG?

A

Progression free survival median

93
Q

Current standard of treatment for DIPGs

A

Semi urgent basis treatment
54Gy in 30 fnx over 6 weeks
CTV margin of 1-1.5 cm

94
Q

What is the percentage of intramedullary spinal cord tumor of all CNS tumor in pediatric age group?

A

3-6%

95
Q

What are the majority of intramedullary spinal cord tumor type?

A

60% are LGAs
30% ependymoma
Remainder are ganglioganglioma, teratoma, lipoma, dermis and epidermis cyst

96
Q

Describe imaging finding of Astrocytoma of spinal cord

A

Solid component with one or more cysts, enhance heterogenously with use of contrast

97
Q

What percentage of children with Pilocytic Astrocytoma can undergo complete or subtotal resection with routine use of surgical adjunct such as ultrasonic aspiration , intra operative ultrasound, sensory and motor evoked potential monitoring?

A

80%

98
Q

What is long term progression free survival after surgery in LGAs of spinal cord?

A

70-90%

99
Q

What is the treatment option if total or subtotal resection is not possible?

A

Second surgery

Close follow up with second surgery and RT at time of progression

100
Q

What is the treatment option for LGAs Spinal cord for young children?

A

Chemotherapy

101
Q

What is treatment option for HGAs spinal cord ?

A

Biopsy followed by RT

Role of surgery is less clear

102
Q

Describe target delineation for LGAs spinal cord

A

50.4Gy in 28 fnx over 6 weeks

CTV 1-1.5 cm

103
Q

Describe target delineation for HGAs spinal cord

A

50.4Gy in 28 fnx over 6 weeks

CTV atleast 1.5cm or one vertebral body

104
Q

Describe WHO classification of ependymoma tumors of spinal cord

A

Grade I Myxopapillary Ependymoma
Grade II Ependymoma
Grade III Anaplastic Ependymoma

105
Q

Myxopapillary Ependymoma is almost always located in what part of spinal cord?

A

Conus filum terminale

106
Q

Myxopapillary Ependymoma, what should be the initial imaging work up and why?

A

MRI whole spine and brain

Because leptomeningeal metastasis is not uncommon

107
Q

What is treatment of choice in Myxopapillary Ependymoma?

A

Surgery

108
Q

With local recurrence or leptomeningeal mets, what is treatment options for Myxopapillary Ependymoma?

A

Further surgery and RT

109
Q

Leptomeningeal spread at diagnosis or relapse after surgery without RT, treatment option for Myxopapillary Ependymoma spinal cord

A

CSI followed by boost to primary site

110
Q

Describe RT for tumor recurrence in Myxopapillary Ependymoma spinal cord?

A

50.4Gy

CTV margin 1.5cm or one vertebral body

111
Q

3rd most common CNS tumor in children

A

Ependymoma

112
Q

What is the age group in children who acquire Ependymoma?

A

Half of all cases younger than 5 years

113
Q

Most common site of Ependymoma in ventricular system or spinal cord

A

2/3rd cases in Ependymoma lining of 4th ventricle

114
Q

Most common presentation of Ependymoma

A

Symptoms and sign of increased intracranial pressure

115
Q

Describe imaging features of Ependymoma

A

Tumor is usually large
Well circumscribed
Displacement rather than invasion of adjacent structures

116
Q

Describe mode of spread of Ependymoma

A

Primarily local

5-10% have leptomeningeal spread at diagnosis

117
Q

Essential work up of Ependymoma

A

MRI whole CNS and CSF cytology

118
Q

What percentage of complete surgical resection can be achieved in Supratentorial Ependymoma?

A

70-90%

119
Q

Describe general principle of Ependymoma

A

Complete resection followed by post-operative RT for all children older than 12 months

120
Q

What is the standard of care for infratentorial ependymoma?

A

Local RT since there is no evidence that use of CSI affects outcome

121
Q

Describe target delineation for Ependymoma

A

GTV = tumor bed + any extension caudal to foramen magnum + any anatomic shift due to surgery+ any residual tumor

CTV = 0.5cm(COG) - 1cm(St. Jude prospective study)

122
Q

What is standard of dose for supra- and infra-tentorial ependymoma ?

A

54Gy

123
Q

What is the dose recommendation of spinal ependymoma?

A

45-50Gy

124
Q

Role of chemotherapy in Ependymoma

A

Unclear

COG baby study showed prolonged use of chemotherapy and delay of RT more than 1 year associated with worse survival

125
Q

Describe histologic features of anaplastic ependymoma

A

High Mitotic index
Microvascular proliferation
Pseudopalisading necrosis

126
Q

Describe general principle of treatment of anaplastic ependymoma

A

Maximal surgical resection followed by RT in all patients

127
Q

What is the dose prescription for anaplastic ependymoma

A

54-60Gy

128
Q

Describe target delineation for anaplastic ependymoma

A

Tumor bed with any macroscopic residual disease with CTV margin of 1 cm

129
Q

What is event free survival and overall survival for anaplastic ependymoma?

A

St. Jude series
Event free survival at 7 years is 61.3%
Overall survival 71.8%

130
Q

WHO classification of choroid plexus tumor

A

Grade I Choroid Plexus Papilloma
Grade II Atypical Choroid Plexus Papilloma
Grade III Choroid Plexus Carcinoma

131
Q

What is the percentage of Choroid Plexus tumor of all brain tumors in children

A

2-4%

132
Q

Which is the common type of Choroid Plexus tumor?

A

Choroid Plexus Papilloma accounts more than half of tumor type

133
Q

Choroid plexus tumor arise from mostly which part of ventricle?

A

Lateral ventricle

134
Q

What should be the initial imaging work up and why in choroid plexus tumors?

A

Gadolinium enhanced MRI spinal axis and CSF cytology

Because even papilloma seed into CSF space

135
Q

Describe general principle of treatment for choroid plexus papilloma

A

Surgery with complete resection
Follow up without adjuvant treatment
Further surgery if feasible after incomplete resection

136
Q

What is the indication of RT in choroid plexus papilloma?

A

Tumor progression despite tumor resection

137
Q

What is the percentage of tumor recurrence and overall survival in CPP?

A

Tumor recurrence 10%

Overall survival 100%

138
Q

Describe general principle of treatment in Choroid Plexus Carcinoma

A

Surgery if feasible but often difficult
Postoperative RT appears to be useful
Chemotherapy can be used to delay RT until 3 years old
When both are used, RT is delivered early after 2 cycles of Chemo

139
Q

What RT approach can be used with atypical CPP or CPC

A

CSI with leptomeningeal spread

140
Q

Name 2 mixed neuronal-glial tumor type where RT is indicated

A

Ganglioglioma and Anaplastic ganglioglioma

Central Neurocytoma

141
Q

What is the common location of Ganglioglioma or Atypical ganglioglioma?

A

Temporal region

142
Q

What is the common presentation of Ganglioglioma or Atypical Ganglioglioma?

A

Seizure

143
Q

What is treatment of choice for Ganglioglioma or Atypical Ganglioglioma?

A

Surgery

144
Q

What is the role of RT in mixed neuronal-glial tumors?

A

Anaplastic Ganglioglioma and central Neurocytoma with incomplete resection only

145
Q

What is the dose prescription if RT is indicated in central neurocytoma?

A

Typical Neurocytoma 50Gy

Atypical Neurocytoma 54Gy

146
Q

What is the percentage of pineal region tumors in children?

A

2-8%

147
Q

What is the common tumor type in pineal gland?

A

Approximately half of the pineal gland tumor are germ cell tumors

148
Q

WHO classification of pineal parenchymal tumors

A

Pineocytoma Grade I
Pineal parenchymal tumor of intermediate differentiation Grade II/III
Pineoblastoma Grade IV

149
Q

Which is the common tumor type in pineal parenchymal tumors?

A

Approximately half are Pineocytoma

150
Q

What is the MRI finding of Pineocytoma?

A

Spherical
Well circumscribed
Hypointense on T1, Hyperintense on T2
Homogenous contrast enhancement

151
Q

Describe general principle of treatment of Pineocytoma

A

Surgical resection via occipital transtentorial approach or infratentorial supracerebellar approach with functional MRI
Postoperative RT

152
Q

What is percentage of progression free survival after complete or subtotal resection in Pineocytoma?

A

90-100%

153
Q

Describe target delineation and dose prescription in Pineocytoma

A

CTV margin 1 cm

Dose 50-55Gy

154
Q

Describe histologic features of pineoblastoma

A

Patternless sheets of densely packed small cells with round to irregular nuclei and scanty cytoplasm

155
Q

Define age group of pineoblastoma

A

Infants and very young children

156
Q

Describe MRI findings in pineoblastoma

A

Multilobulated
Heterogenously enhancing
Area of necrosis and/or hemorrhage
Infiltrative

157
Q

What percentage of pineoblastoma shows leptomeningeal spread?

A

50%

158
Q

Describe general principle of treatment of pineoblastoma

A

Surgery followed by RT(CSI) and chemotherapy in children older than 3 years

159
Q

What is the period of tumor recurrence in children treated with chemotherapy without RT?

A

Within first 11 months - POG

Within first 1.2 years - CCG

160
Q

What is trilateral retinoblastoma?

A

Bilateral retinoblastoma with Pineoblastoma

161
Q

What is the second most common CNS tumor in pediatric age group?

A

Embryonal tumors like Medullobalstoma, Supratentorial PNET

162
Q

What is the percentage of Medulloblastoma of all CNS tumors in children?

A

15-20%

163
Q

Where is the common origin of medulloblastoma?

A

Cerebellar vermis

164
Q

What is the percentage of leptomeningeal spread in medulloblastoma?

A

30-35%

165
Q

What post operative period can lumbar puncture be performed to avoid false positives?

A

After 2 weeks

166
Q

Medullobalstoma can spread extracranially to which sites?

A

Lymph nodes and bone

167
Q

What are the factors that correlate with outcome of medulloblastoma?

A

Age at diagnosis
Presence or absence of leptomeningeal spread at diagnosis
Completeness of surgical resection

168
Q

Define standard risk medulloblastoma

Which histologic cell type is consider to have standard risk for recurrence in medulloblastoma ?

A

Tumor residual

169
Q

Define high risk medulloblastoma

Which histologic cell type has unfavorable features to consider high risk for recurrence in medulloblastoma ?

A

Tumor residual >1.5cm3
With evidence of CSF dissemination

Large Cell or Anaplastic

170
Q

What is the percentage of complete or near complete resection in medulloblastoma

A

80%

171
Q

Standard of care for children older than 3 years with standard risk medulloblastoma

A
  1. CSI to 35-36Gy+Posterior fossa boost to 54-55.8Gy

2. Reduced dose CSI(23.4Gy) + PFB to 54-55.8Gy followed by systemic chemotherapy

172
Q

Chemotherapy used in standard risk medulloblastoma

A
CCG pilot study 
Weekly vincristine followed by adjuvant systemic chemo
Vincristine 1.5mg/m2
CCNU 75mg/m2
Cisplatinum 75mg/m2
173
Q

Standard of care for children older than 3 years with High risk medulloblastoma

A

CSI to 35-36Gy+Posterior fossa boost to 54-55.8Gy and post-RT Chemotherapy

174
Q

What percentage of medulloblastoma accounts for CNS tumors in infants?

A

20-40%

175
Q

Describe M-stage in medulloblastoma

M0-M4

A

M0 - No evidence of metastasis
M1 - Tumor cells are found in CSF by lumber puncture or cell cytology
M2 - Tumor beyond primary site but still in brain
M3 - Tumor deposits in spine area that are easily seen in MRI
M4 - Tumor spreads to areas outside CNS

176
Q

Prognosis in infants is worst compared to older children in medulloblastoma because?

A

Tumor biology
Lower rate of complete resection
Higher frequency of leptomeningeal seeding at diagnosis
Many patient don’t receive optimal treatment

177
Q

What is the recurrence period of medulloblastoma?

A

6-12 months

178
Q

Standard of care for infant with standard risk of recurrence medulloblastoma according to North American Study
Nodular or desmoplastic
Without residual
Without leptomeningeal spread

A

RT with limited treatment volume of tumor bed + CTV margin of 1 cm

179
Q

What is the treatment regimen for M2/M3 medulloblastoma in infants?

A

Intensive chemotherapy with RT highly individualized based on clinical situation and wishes of parents.

Experimental in stPNET

180
Q

Relapse rate that correlated with target deviation

MSFOP-93 and MSFOP-98

A

Relapse Rate Inadequate coverage
17% 1 site eg cribiform plate
28% 2 sites
67% 3 sites or more

181
Q

Describe reduced volume PFB for standard risk medulloblastoma

A

GTV (macroscopic residual tumor+surgical bed) + 1.5 cm margin
This volume is under investigation in current COG study

182
Q

Event free and overall survival were significantly worst when duration of treatment exceeded what period in medulloblastoma?

A

50 days

As compared to 45-47 days in SIOP PNET-3 study

183
Q

What is recommended when CSI is interrupted because of toxicity?

A

Treatment should continue to posterior fossa boost while toxicity recovers.

184
Q

Define stPNET

A

Supratentorial Primitive Neuroectodermal Tumor are embryonal tumor composed of undifferentiated or poorly differentiated neuroepithelial cells

185
Q

Enumerate Supratentorial Primitive Neuroectodermal Tumor

A

Cerebral neuroblastoma or Ganglioneuroblastoma
Medulloepithelioma
Ependymoblastoma

186
Q

What are imaging findings of stPNET?

A

Heterogenous with cystic or necrotic areas and areas of hemorrhage

187
Q

What is the percentage of leptomeningeal seeding present at diagnosis in stPNET?

A

40%

188
Q

What is general principle of treatment of stPNET?

A
Approach similar to high risk medulloblastoma
Post operative (standard dose CSI + boost)and chemotherapy
189
Q

What is the overall survival of stPNET?

A

30-50%

190
Q

What are better prognostic factors of stPNET?

A

Smaller size

191
Q

What are bad prognostic factors of stPNET?

What is overall survival with bad prognostication?

A

Younger age
M+

0-30%

192
Q

What is the failure rate in medulloblastoma with M0 and M+?

A

Local failure with M0 is 42%

Leptomeningeal failure with M+ is 43%

193
Q

What age group Atypical Teratoid/Rhabdoid tumor(ATRT) are seen?

A

Birth to 2 years

194
Q

What is the location of ATRT?

A

Any location within CNS including spine

195
Q

Prognosis of ATRT with leptomeningeal spread

A

Very poor

196
Q

Describe general principle of treatment of ATRT

A

Early RT(after 2 cycles of chemo)
Children younger than 6 mths with infratentorial tumor and younger than 12 mths with Supratentorial tumor receive RT after completion of chemo
Local RT with 1 cm CTV margin for localized disease and CSI for leptomeningeal spread

197
Q

Incidence of CNS germ cell tumors

A

15-18% of all CNS tumors Asia

3-5% West

198
Q

Where is the common location of CNS germ cell tumors?

A

Most common pineal gland

Second most common suprasellar region

199
Q

Describe imaging findings of CNS germ cell tumors

A

Solid mass
Teratoma are heterogenous with cyst, area of calcification, fat
Choriocarcinoma areas of hemorrhage

200
Q

What is the percentage of meningeal dissemination in CNS germ cell tumors?

A

10% Germinoma

10-15% NGGCT

201
Q
Measurement of serum and CSF tumor markers in
Germinoma
NGGCT
   Choriocarcinoma
   Yolk sac tumor
A

Germinoma B-HCG modest elevation 100IU/mL

Yolk sac tumor AFP elevated

202
Q

Most common location of NGGCTs

A

Pineal region

203
Q

Most common location of Germinoma

A

Suprasellar region

204
Q

Describe general principle of management of germinoma

A

Total dose to primary site 40-45Gy/1.5Gy(whole ventricular irradiation 30-36Gy)
CSI with leptomeningeal spread 21Gy
Chemotherapy with complete response followed by RT 24-30Gy

205
Q

What is the disease free survival rate platinum based chemo followed by reduced volume, reduced dose RT

A

90-96%

206
Q

Classify NGGCT according to prognosis

A
Good prognosis mature teratoma
Intermediate prognosis 
   Immature teratoma
   Mixed germ cell tumor(germinoma with mature or immature teratoma)
Poor prognosis
   Teratoma 
   Embryonal carcinoma
   Yolk sac tumor
   Choriocarcinoma
   Mixed germ cell tumor
207
Q

Treatment of mature teratoma

A

Surgery alone

208
Q

Treatment of intermediate and poor prognosis NGGCTS

A

Platinum based chemo followed by RT

209
Q

What is the dose prescription for NGGCTs

A

Whole ventricular volume or CSI 30-36Gy

Primary site 54Gy

210
Q

What are tumors of seller region?

A

Craniopharyngioma

Pituitary adenoma

211
Q

Where is the origin of craniopharyngioma?

A

Remnants of rathke’s pouch

212
Q

What is the common presentation of craniopharyngioma

A

Neuroendocrine deficits like diabetes insipidus and growth failure

213
Q

What are imaging findings in craniopharyngioma

A

Solid and cystic area in varying proportion
Calcification is seen in majority
Solid portion and cystic capsule enhances with use of contrast

214
Q

What is the long term tumor control(event free survival) at 3 years in craniopharyngioma

A

64%

215
Q

What are indications of surgery in craniopharyngioma?

A

Smaller tumor
Sub diaphragmatic in location
Without hypothalamic involvement

216
Q

Post surgery, what is the period of disease progression in craniopharyngioma?

A

Within first 2-3 years post surgery

217
Q

What are indications of RT in craniopharyngioma?

A

Sole therapy after biopsy
After imcomplete surgery or time of progression /recurrence after surgery
Tumor heterogeneity

218
Q

Describe target delineation and dose in craniopharyngioma

A

GTV + CTV margin varying from 0-0.5-1cm

54-55Gy

219
Q

What changes can we expect in initial 2-3 months post-RT?

A

Cyst enlargement

220
Q

What is the advantage of early recognition and cyst decompression in craniopharyngioma?

A

To further avoid neurologic compromise

221
Q

What is the event free survival of craniopharyngioma?

A

80-100%

222
Q

What are common presentation of functioning adenoma in each sex?

A

Menstrual irregularities and galactorrhea in girls

Delayed puberty in boys

223
Q

How do we manage prolactin and growth harmone secreting adenoma?

A

Medical management

224
Q

What is the indication of RT in pituitary adenoma?

A

Surgery not possible

Harmone remains elevated following surgery

225
Q

Describe dose prescription and target delineation in pituitary adenoma?

A

GTV + CTV of 0.5 cm

45-50 Gy