Chapter 84 CNS Tumors In Children Flashcards
What percentage of childhood malignancies known with genetic predisposition?
2-5%
What are the genetic predisposition in childhood malignancies?
- Neurofibromatosis types 1(NF-1) and 2 (NF-2)
- Tuberous Sclerosis
- Nevoid basal cell(Gorlin’s) syndrome
- Familial adenomatous polyposis
- Li-Fraumeni syndrome
What is the main predisposing factor of childhood malignancies?
Majority remains with no predisposing factors
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?
- Age at treatment
- Tumor location
- Treatment factors(RT volume, dose and use of chemotherapy)
What intervention could be used for helping patients with RT induced deficits?
The following can be start soon after treatment for best results
- Cognitive or behavioral therapy
- Pharmacotherapy
- Exercise
Endocrine deficit are very common after RT. Which harmone deficiency is primarily responsible that correlates with dose of RT?
Growth harmone
Which harmone deficiency is primarily responsible that is seen after CSI?
Thyroid harmone
What percentage of CNS malignancies occurs in childhood?
20-25%
What strategies could be used to avoid or minimize long term effects of treatment for pediatric brain tumor?
- Avoidance of RT altogether
- Delay of RT for age 3-8 years by chemotherapy
- Use of daily anesthesia, improved immobilization, daily pretreatment image verification
- Use of new RT modalities eg Proton
- Use of reduced RT target volume eg in medulloblastoma
- Reduce RT dose eg in medulloblastoma
- Use of small fraction size in radiosensitive tumor eg germinoma 1.5Gy/Fx
- HFRT eg current Europian studies in Medulloblastoma
During patient positioning and immobilization in CSI, what maneuver will help avoid dentition in exit dose from superior aspect of spinal field?
Neck extension with careful selection of level for junction of brain and spinal fields
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?
MRI findings
During CSI, what percentage of variation of dose along spinal axis will require use of dose compensation and how can we achieve that?
> 10%
Using MLC
What are possible solutions for field matching over cervical spine/risk of over- or under dosage?
- Angle brain fields
- Use half beam blocks for brain fields
- Use couch rotation or match line wedge
What are possible solutions for irradiation of normal tissue thyroid gland?
Care of level of junction
Most common CNS tumor in pediatric age group?
Medulloblastoma
Most common CNS tumors in adult group?
High grade glioma
WHO classification of Astrocytic tumors Grade I Grade II Grade III Grade IV
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
What are low grade glioma?
What is the overall survival rates at 10 and 15 years
Grade I/II
80-100%
Group LGGs according to an anatomic locations
Cerebellar Astrocytoma Hemispheric Astrocytoma Midline Supratentorial tumors Corpus Callosum Lateral and third ventricle Hypothalamus Thalamus Optic pathway tumors Brainstem LGAs LGAs of Spinal Cord
What is most common Astrocytoma in pediatric age group?
Pilocytic Astrocytoma
Name the sites accounting for almost all of LGAs, Pilocytic
Cerebellum
Anterior Optic Pathway
Describe macroscopic features of Pilocytic Astrocytoma
Well circumscribed, associated cystic component.
Describe microscopic features of Pilocytic Astrocytoma
Biphasic pattern
- Varying proportion of compacted bipolar cells with Rosenthal fibers
- Loosely textured multipolar cells with microcysts and granular bodies
Features compatible with Pilocytic Astrocytoma but not a sign of malignancy
Rare mitosis
Occasional hyperchromatic nuclei
Micro vascular proliferation
Infiltration of meninges
Large proportion of diffuse astrocytoma arise from?
Intrinsic pontine tumors
Cerebral hemisphere
Describe macroscopic features of diffuse astrocytoma
Infiltration rather than destruction of anatomic structure
Usually not well circumscribed
Describe microscopic features of diffuse astrocytoma
- Well differentiated fibrillary or gemistocytic neoplastic astrocytoma on a background of loosely structured often microcystic tumor matrix
- Presence of nuclear atypia is diagnostic criterion
- Mitotic activity, necrosis, microvascular proliferation are absent
Symptoms relate to location of tumors
- Hemispheric tumor
- Hypothalamic tumor
- Diencephalic syndrome
- Focal motor deficit
- Neuro endocrine deficit
- Emaciation with loss of subcutaneous fat despite normal or increased appetite , alert appearance, increased vigor and euphoria, pallor without anemia, nystagmoid movement of eyes.
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
- NF-1 with optic pathway tumor
2. LGAs with tectal lesion with hydrocephalus without localizing brain stem signs.
What percentage of complete resection is achieved in cerebral, cerebellar, spinal cord tumors?
What percentage of complete resection is achieved in diencephalic tumor?
> 80%
50%
In joint CCG-POG study, subtotal resection without adjuvant treatment, what is 8 years progression free survival and overall survival rates?
PFS with 1.5 cm3 residual 45%
OS with 1.5cm3 residual 90%
What is the role of post-operative radiotherapy in less than complete tumor resection?
It results in improved disease free survival without benefit in overall survival
What is the period for risk of disease progression after incomplete tumor resection?
Initial 3 years after incomplete tumor resection
When does second surgery be considered?
When does other treatment be reserved like RT and Chemotherapy?
At tumor progression and operable
At tumor progression and inoperable
What is the indication of adjuvant chemotherapy particularly in infant and young children and patient of all ages with NF-1?
Patient are greatest risk of developing neuro cognitive, vaso-occlusive and neuroendocrine sequelae of RT treatment.
What is the overall response rate in terms of stable disease to chemotherapy as adjuvant therapy in LGAs?
70-100%
How long can chemotherapy permit delay of RT?
2 to 4+ years
What age group benefit delay of RT by using chemotherapy?
5-8 years
CTV margin for pilocytic astrocytoma?
0-1 cm around GTV in T1 weighted gadolinium enhanced images
CTV margin for infiltrative diffuse fibrillary astrocytoma?
1-1.5 cm around GTV seen in T2 weighted or Flair images
What is standard dose of LGAs?
50-54Gy
What are radioactive solutions used in recurrent LGAs after RT where symptoms relate more to cyst wall than solid component of tumor?
32P
90Y
198Au
186Re
Post RT MRI in initial months shows no change in tumor volume or rather increase in size..what should you do next?
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.
What percentage of high grade astrocytoma accounts for all CNS tumors in pediatric age group?
5%
What comprises of HGAs?
Grade III Anaplastic Astrocytoma(AA)
Grade IV GBM
Describe 6 histopathologic features of HGAs
Nuclear atypia Cellular pleomorphism Mitotic activity Vascular thrombosis Microvascular proliferation Necrosis
HGAs is common in what age group?
Older adolescent
What are the common sites of HGAs?
2/3 cerebral hemisphere
Remaining : deep midline structures thalamus, basal ganglia, cerebellum
What is the predominant failure pattern in HGAs?
Local
What is the percentage of leptomeningeal spread in HGAs?
10-30%
Describe the basic principle of treatment in HGAs
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
Describe target delineation in HGAs
GTV of tumor bed, residual enhancing or non enhancing residual tumor plus abnormality seen in T2 weighted MRI with CTV margin of 1.5cm
What is dose prescription in HGAs?
54-60 Gy standard dose
50-54Gy if dose tolerance of normal organ like optic chiasm exceeds its dose constrain
What chemotherapy can be used in adult HGAs ?
Temozolamide
What is median time of progression and overall survival at 5 years of HGAs in children
Median time of progression 10-11 months
Overall survival 20%
In HGAs, by location which has good and bad prognosis?
Good prognosis cerebral hemisphere
Bad prognosis thalamic lesion
In HGAs, by age which has good and bad prognosis?
Good prognosis younger than age 3
Bad prognosis older children more than 3 years
p53 over expression and MIB-1 labeling index has good or bad prognosis?
Bad prognosis
What is the age group of optic pathway glioma?
2-6 years
75% are younger than 10 years
1/3rd of optic pathway glioma is associated with what genetic predisposing factor?
Bilateral optic nerve involvement is pathognomonic of?
NF-1
Name 3 clinicopathologic entities of optic pathway glioma
- Tumor confined to optic nerve
- Anterior tumor : tumor confined to optic chiasm
- Posterior or chiasmatic/hypothalamic tumor(70%) : tumor involve hypothalamus or adjacent structure
Describe general principle of treatment of optic pathway glioma
Surgical resection if no useful vision
Chemotherapy for infants and age up to 5 years if useful vision
Radiotherapy for older children
What is the long term tumor control rate with chemotherapy or radiotherapy in optic pathway glioma?
100%
Describe general principle of chiasmatic glioma
- Surgery is NO option
- NF-1 and younger than 5 years : Surveillance is appropriate initial management or Chemotherapy
- Without NF-1 and older children : radiotherapy is reserved for salvage after chemotherapy
Long term progression free survival and overall survival in chiasmatic glioma
Long term progression free survival 60-90%
Overall survival 90-100%
What are early and late findings of posterior or chiasmatic/hypothalamic glioma?
Early findings : nystagmus, impaired visual acuity, visual field defects
Late findings : increased head circumference, signs and symptoms of increased ICP
Describe general principles of posterior or chiasmatic/hypothalamic glioma
- CSF diversion and surgical resection
- Chemotherapy NF-1 with younger than 5 years
- Radiotherapy without NF-1 with older children, disease progression with chemotherapy, disease progression at diagnosis or after surgery.
What is dose prescription of posterior or chiasmatic/hypothalamic glioma
45-50 Gy younger children
50-54 Gy older children above 5 years
What is the local tumor control with RT in posterior or chiasmatic/hypothalamic glioma?
70-80%
What is the long term survival in posterior or chiasmatic/hypothalamic glioma?
50-80%
Patient of posterior or chiasmatic/hypothalamic glioma with NF-1, how do we do follow up?
MR angiography as part of regular follow up imaging protocol and intervene surgically if necessary to avoid CVA
Why do we need MR angiography for follow up of patient with posterior or chiasmatic/hypothalamic glioma?
With NF-1 they are at greatest risk of moyamoya syndrome, a progressive vasocclusive process involving circle of willis
What percentage of brainstem glioma comprises of all CNS tumors in pediatric age group?
10-15%
Name favorable groups of brainstem glioma
Low grade focal
Dorsal exophytic
Cervicomedullary tumors
Name more aggressive brainstem glioma
Diffuse intrinsic pontine glioma
Describe features of low grade focal brainstem glioma
Well circumscribed, cystic, without evidence of infiltration, without edema
Describe general principle of treatment of low grade focal brainstem glioma
Surgery in experienced hands for well selected cases
Standard RT of 54Gy over 6 weeks with CTV margin of 0.5cm
What are the factors that depends on outcome of conventional RT in low grade focal brainstem glioma?
- location - pons vs others
- Imaging appearance - tumor volume, density on CT, enhancement pattern)
- Histology - malignant vs benign
Describe radiological findings of dorsal exophytic brainstem glioma
MRI sharply delineated from surrounding tissue
Hypointense on T1
Hyperintense on T2
Enhance uniformly and brightly after gadolinium
What is most common histology of tumor in dorsal exophytic brainstem glioma
Pilocytic astrocytoma
What is the treatment of choice for dorsal exophytic brainstem glioma
Surgery
What is the indication of RT in dorsal exophytic brainstem glioma
Routine postoperative RT NOT indicated
Should be considered for
High grade lesion
Disease progression in early
Treatment strategy for tumor recurrence in dorsal exophytic brainstem glioma
Further surgery and RT
How is the overall prognosis of dorsal exophytic brainstem glioma
Excellent
What is the treatment choice for cervicomedullary brainstem glioma
Surgery
What is the gross total resection rate of cervicomedullary brainstem glioma
70-80%
What is the indication of RT in cervicomedullary brainstem glioma?
NO indication of RT
What is the common histology of tumor in diffuse intrinsic pontine brainstem glioma
Fibrillary Astrocytoma
Name cranial nerves commonly involved in diffuse intrinsic pontine tumors
CN VI and VII
Describe radiologic feature of diffuse intrinsic pontine brainstem glioma
Best seen in T2 or FLAIR
Ring enhancement suggestive of high grade histology
What is the indication of surgery in diffuse intrinsic pontine brainstem glioma
Surgery has NO role
What is the progression free survival, survival rate at 2 years in DIPG?
Progression free survival median
Current standard of treatment for DIPGs
Semi urgent basis treatment
54Gy in 30 fnx over 6 weeks
CTV margin of 1-1.5 cm
What is the percentage of intramedullary spinal cord tumor of all CNS tumor in pediatric age group?
3-6%
What are the majority of intramedullary spinal cord tumor type?
60% are LGAs
30% ependymoma
Remainder are ganglioganglioma, teratoma, lipoma, dermis and epidermis cyst
Describe imaging finding of Astrocytoma of spinal cord
Solid component with one or more cysts, enhance heterogenously with use of contrast
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?
80%
What is long term progression free survival after surgery in LGAs of spinal cord?
70-90%
What is the treatment option if total or subtotal resection is not possible?
Second surgery
Close follow up with second surgery and RT at time of progression
What is the treatment option for LGAs Spinal cord for young children?
Chemotherapy
What is treatment option for HGAs spinal cord ?
Biopsy followed by RT
Role of surgery is less clear
Describe target delineation for LGAs spinal cord
50.4Gy in 28 fnx over 6 weeks
CTV 1-1.5 cm
Describe target delineation for HGAs spinal cord
50.4Gy in 28 fnx over 6 weeks
CTV atleast 1.5cm or one vertebral body
Describe WHO classification of ependymoma tumors of spinal cord
Grade I Myxopapillary Ependymoma
Grade II Ependymoma
Grade III Anaplastic Ependymoma
Myxopapillary Ependymoma is almost always located in what part of spinal cord?
Conus filum terminale
Myxopapillary Ependymoma, what should be the initial imaging work up and why?
MRI whole spine and brain
Because leptomeningeal metastasis is not uncommon
What is treatment of choice in Myxopapillary Ependymoma?
Surgery
With local recurrence or leptomeningeal mets, what is treatment options for Myxopapillary Ependymoma?
Further surgery and RT
Leptomeningeal spread at diagnosis or relapse after surgery without RT, treatment option for Myxopapillary Ependymoma spinal cord
CSI followed by boost to primary site
Describe RT for tumor recurrence in Myxopapillary Ependymoma spinal cord?
50.4Gy
CTV margin 1.5cm or one vertebral body
3rd most common CNS tumor in children
Ependymoma
What is the age group in children who acquire Ependymoma?
Half of all cases younger than 5 years
Most common site of Ependymoma in ventricular system or spinal cord
2/3rd cases in Ependymoma lining of 4th ventricle
Most common presentation of Ependymoma
Symptoms and sign of increased intracranial pressure
Describe imaging features of Ependymoma
Tumor is usually large
Well circumscribed
Displacement rather than invasion of adjacent structures
Describe mode of spread of Ependymoma
Primarily local
5-10% have leptomeningeal spread at diagnosis
Essential work up of Ependymoma
MRI whole CNS and CSF cytology
What percentage of complete surgical resection can be achieved in Supratentorial Ependymoma?
70-90%
Describe general principle of Ependymoma
Complete resection followed by post-operative RT for all children older than 12 months
What is the standard of care for infratentorial ependymoma?
Local RT since there is no evidence that use of CSI affects outcome
Describe target delineation for Ependymoma
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)
What is standard of dose for supra- and infra-tentorial ependymoma ?
54Gy
What is the dose recommendation of spinal ependymoma?
45-50Gy
Role of chemotherapy in Ependymoma
Unclear
COG baby study showed prolonged use of chemotherapy and delay of RT more than 1 year associated with worse survival
Describe histologic features of anaplastic ependymoma
High Mitotic index
Microvascular proliferation
Pseudopalisading necrosis
Describe general principle of treatment of anaplastic ependymoma
Maximal surgical resection followed by RT in all patients
What is the dose prescription for anaplastic ependymoma
54-60Gy
Describe target delineation for anaplastic ependymoma
Tumor bed with any macroscopic residual disease with CTV margin of 1 cm
What is event free survival and overall survival for anaplastic ependymoma?
St. Jude series
Event free survival at 7 years is 61.3%
Overall survival 71.8%
WHO classification of choroid plexus tumor
Grade I Choroid Plexus Papilloma
Grade II Atypical Choroid Plexus Papilloma
Grade III Choroid Plexus Carcinoma
What is the percentage of Choroid Plexus tumor of all brain tumors in children
2-4%
Which is the common type of Choroid Plexus tumor?
Choroid Plexus Papilloma accounts more than half of tumor type
Choroid plexus tumor arise from mostly which part of ventricle?
Lateral ventricle
What should be the initial imaging work up and why in choroid plexus tumors?
Gadolinium enhanced MRI spinal axis and CSF cytology
Because even papilloma seed into CSF space
Describe general principle of treatment for choroid plexus papilloma
Surgery with complete resection
Follow up without adjuvant treatment
Further surgery if feasible after incomplete resection
What is the indication of RT in choroid plexus papilloma?
Tumor progression despite tumor resection
What is the percentage of tumor recurrence and overall survival in CPP?
Tumor recurrence 10%
Overall survival 100%
Describe general principle of treatment in Choroid Plexus Carcinoma
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
What RT approach can be used with atypical CPP or CPC
CSI with leptomeningeal spread
Name 2 mixed neuronal-glial tumor type where RT is indicated
Ganglioglioma and Anaplastic ganglioglioma
Central Neurocytoma
What is the common location of Ganglioglioma or Atypical ganglioglioma?
Temporal region
What is the common presentation of Ganglioglioma or Atypical Ganglioglioma?
Seizure
What is treatment of choice for Ganglioglioma or Atypical Ganglioglioma?
Surgery
What is the role of RT in mixed neuronal-glial tumors?
Anaplastic Ganglioglioma and central Neurocytoma with incomplete resection only
What is the dose prescription if RT is indicated in central neurocytoma?
Typical Neurocytoma 50Gy
Atypical Neurocytoma 54Gy
What is the percentage of pineal region tumors in children?
2-8%
What is the common tumor type in pineal gland?
Approximately half of the pineal gland tumor are germ cell tumors
WHO classification of pineal parenchymal tumors
Pineocytoma Grade I
Pineal parenchymal tumor of intermediate differentiation Grade II/III
Pineoblastoma Grade IV
Which is the common tumor type in pineal parenchymal tumors?
Approximately half are Pineocytoma
What is the MRI finding of Pineocytoma?
Spherical
Well circumscribed
Hypointense on T1, Hyperintense on T2
Homogenous contrast enhancement
Describe general principle of treatment of Pineocytoma
Surgical resection via occipital transtentorial approach or infratentorial supracerebellar approach with functional MRI
Postoperative RT
What is percentage of progression free survival after complete or subtotal resection in Pineocytoma?
90-100%
Describe target delineation and dose prescription in Pineocytoma
CTV margin 1 cm
Dose 50-55Gy
Describe histologic features of pineoblastoma
Patternless sheets of densely packed small cells with round to irregular nuclei and scanty cytoplasm
Define age group of pineoblastoma
Infants and very young children
Describe MRI findings in pineoblastoma
Multilobulated
Heterogenously enhancing
Area of necrosis and/or hemorrhage
Infiltrative
What percentage of pineoblastoma shows leptomeningeal spread?
50%
Describe general principle of treatment of pineoblastoma
Surgery followed by RT(CSI) and chemotherapy in children older than 3 years
What is the period of tumor recurrence in children treated with chemotherapy without RT?
Within first 11 months - POG
Within first 1.2 years - CCG
What is trilateral retinoblastoma?
Bilateral retinoblastoma with Pineoblastoma
What is the second most common CNS tumor in pediatric age group?
Embryonal tumors like Medullobalstoma, Supratentorial PNET
What is the percentage of Medulloblastoma of all CNS tumors in children?
15-20%
Where is the common origin of medulloblastoma?
Cerebellar vermis
What is the percentage of leptomeningeal spread in medulloblastoma?
30-35%
What post operative period can lumbar puncture be performed to avoid false positives?
After 2 weeks
Medullobalstoma can spread extracranially to which sites?
Lymph nodes and bone
What are the factors that correlate with outcome of medulloblastoma?
Age at diagnosis
Presence or absence of leptomeningeal spread at diagnosis
Completeness of surgical resection
Define standard risk medulloblastoma
Which histologic cell type is consider to have standard risk for recurrence in medulloblastoma ?
Tumor residual
Define high risk medulloblastoma
Which histologic cell type has unfavorable features to consider high risk for recurrence in medulloblastoma ?
Tumor residual >1.5cm3
With evidence of CSF dissemination
Large Cell or Anaplastic
What is the percentage of complete or near complete resection in medulloblastoma
80%
Standard of care for children older than 3 years with standard risk medulloblastoma
- 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
Chemotherapy used in standard risk medulloblastoma
CCG pilot study Weekly vincristine followed by adjuvant systemic chemo Vincristine 1.5mg/m2 CCNU 75mg/m2 Cisplatinum 75mg/m2
Standard of care for children older than 3 years with High risk medulloblastoma
CSI to 35-36Gy+Posterior fossa boost to 54-55.8Gy and post-RT Chemotherapy
What percentage of medulloblastoma accounts for CNS tumors in infants?
20-40%
Describe M-stage in medulloblastoma
M0-M4
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
Prognosis in infants is worst compared to older children in medulloblastoma because?
Tumor biology
Lower rate of complete resection
Higher frequency of leptomeningeal seeding at diagnosis
Many patient don’t receive optimal treatment
What is the recurrence period of medulloblastoma?
6-12 months
Standard of care for infant with standard risk of recurrence medulloblastoma according to North American Study
Nodular or desmoplastic
Without residual
Without leptomeningeal spread
RT with limited treatment volume of tumor bed + CTV margin of 1 cm
What is the treatment regimen for M2/M3 medulloblastoma in infants?
Intensive chemotherapy with RT highly individualized based on clinical situation and wishes of parents.
Experimental in stPNET
Relapse rate that correlated with target deviation
MSFOP-93 and MSFOP-98
Relapse Rate Inadequate coverage
17% 1 site eg cribiform plate
28% 2 sites
67% 3 sites or more
Describe reduced volume PFB for standard risk medulloblastoma
GTV (macroscopic residual tumor+surgical bed) + 1.5 cm margin
This volume is under investigation in current COG study
Event free and overall survival were significantly worst when duration of treatment exceeded what period in medulloblastoma?
50 days
As compared to 45-47 days in SIOP PNET-3 study
What is recommended when CSI is interrupted because of toxicity?
Treatment should continue to posterior fossa boost while toxicity recovers.
Define stPNET
Supratentorial Primitive Neuroectodermal Tumor are embryonal tumor composed of undifferentiated or poorly differentiated neuroepithelial cells
Enumerate Supratentorial Primitive Neuroectodermal Tumor
Cerebral neuroblastoma or Ganglioneuroblastoma
Medulloepithelioma
Ependymoblastoma
What are imaging findings of stPNET?
Heterogenous with cystic or necrotic areas and areas of hemorrhage
What is the percentage of leptomeningeal seeding present at diagnosis in stPNET?
40%
What is general principle of treatment of stPNET?
Approach similar to high risk medulloblastoma Post operative (standard dose CSI + boost)and chemotherapy
What is the overall survival of stPNET?
30-50%
What are better prognostic factors of stPNET?
Smaller size
What are bad prognostic factors of stPNET?
What is overall survival with bad prognostication?
Younger age
M+
0-30%
What is the failure rate in medulloblastoma with M0 and M+?
Local failure with M0 is 42%
Leptomeningeal failure with M+ is 43%
What age group Atypical Teratoid/Rhabdoid tumor(ATRT) are seen?
Birth to 2 years
What is the location of ATRT?
Any location within CNS including spine
Prognosis of ATRT with leptomeningeal spread
Very poor
Describe general principle of treatment of ATRT
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
Incidence of CNS germ cell tumors
15-18% of all CNS tumors Asia
3-5% West
Where is the common location of CNS germ cell tumors?
Most common pineal gland
Second most common suprasellar region
Describe imaging findings of CNS germ cell tumors
Solid mass
Teratoma are heterogenous with cyst, area of calcification, fat
Choriocarcinoma areas of hemorrhage
What is the percentage of meningeal dissemination in CNS germ cell tumors?
10% Germinoma
10-15% NGGCT
Measurement of serum and CSF tumor markers in Germinoma NGGCT Choriocarcinoma Yolk sac tumor
Germinoma B-HCG modest elevation 100IU/mL
Yolk sac tumor AFP elevated
Most common location of NGGCTs
Pineal region
Most common location of Germinoma
Suprasellar region
Describe general principle of management of germinoma
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
What is the disease free survival rate platinum based chemo followed by reduced volume, reduced dose RT
90-96%
Classify NGGCT according to prognosis
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
Treatment of mature teratoma
Surgery alone
Treatment of intermediate and poor prognosis NGGCTS
Platinum based chemo followed by RT
What is the dose prescription for NGGCTs
Whole ventricular volume or CSI 30-36Gy
Primary site 54Gy
What are tumors of seller region?
Craniopharyngioma
Pituitary adenoma
Where is the origin of craniopharyngioma?
Remnants of rathke’s pouch
What is the common presentation of craniopharyngioma
Neuroendocrine deficits like diabetes insipidus and growth failure
What are imaging findings in craniopharyngioma
Solid and cystic area in varying proportion
Calcification is seen in majority
Solid portion and cystic capsule enhances with use of contrast
What is the long term tumor control(event free survival) at 3 years in craniopharyngioma
64%
What are indications of surgery in craniopharyngioma?
Smaller tumor
Sub diaphragmatic in location
Without hypothalamic involvement
Post surgery, what is the period of disease progression in craniopharyngioma?
Within first 2-3 years post surgery
What are indications of RT in craniopharyngioma?
Sole therapy after biopsy
After imcomplete surgery or time of progression /recurrence after surgery
Tumor heterogeneity
Describe target delineation and dose in craniopharyngioma
GTV + CTV margin varying from 0-0.5-1cm
54-55Gy
What changes can we expect in initial 2-3 months post-RT?
Cyst enlargement
What is the advantage of early recognition and cyst decompression in craniopharyngioma?
To further avoid neurologic compromise
What is the event free survival of craniopharyngioma?
80-100%
What are common presentation of functioning adenoma in each sex?
Menstrual irregularities and galactorrhea in girls
Delayed puberty in boys
How do we manage prolactin and growth harmone secreting adenoma?
Medical management
What is the indication of RT in pituitary adenoma?
Surgery not possible
Harmone remains elevated following surgery
Describe dose prescription and target delineation in pituitary adenoma?
GTV + CTV of 0.5 cm
45-50 Gy