Pediatric HGG

Question 1

What percent of pediatric tumors are HGG

Answer 1

12%

Question 2

What percentage will disseminate

Answer 2

Around 25-50% will disseminate

Question 3

What is the median survival

Answer 3

1-2 years
Infants usually do better

Question 4

What is the workup

Answer 4

H&P
Neurological exam
MRI
Biopsy from tumor whenever possible
Max safe resection
Post op MRI

Question 5

Which group has H3 and H3.1 mutations and what do these mutations cause

Answer 5

Only in kids
These mutations lead to global hypomethylation

Question 6

What % of DIPGs have H3K27 mutation

Answer 6

85%

Question 7

What % of childhood diffusely infiltrating glioma do not have H3 mutations

Answer 7

50%

Question 8

Do childhood HGG respond to TMZ

Answer 8

Generally no
Only a subset have MGMT hypermethylation
H3.3 G45R/V subgroup

Question 9

What are prognostic factors for HGG

Answer 9

max safe resection is most important
female gender does a bit better
central is bad
lateralized is good
IDH mutants do better
MGMT overexpression, PTEN mutation, P53 mutations, histone mutations are all bad

Question 10

Describe the treatment paradigm

Answer 10

Max safe resection followed by RT
TMZ sometimes given but there is a lack of efficacy

Question 11

Describe the RT doses and volumes

Answer 11

T1 PG+ cavity+residual disease+T2 FLAIR + 1.5-2 cm (anatomically constrained)—>CTV5040

T1PG residual disease+1 cm–> CTV5940

PTV= CTV+ 3mm

Question 12

What % of pediatric brain tumors are diffuse midline brainstem gliomas

Answer 12

10-20% in pedes vs. 1% in adults
It is the main cause of brain tumor related death in pedes

Question 13

What is the peak age for DMBG

Answer 13

4-6 years

Question 14

What is the differential diagnosis of DMBG

Answer 14

ATRT
PNET
harmatoma
mets
abcess

Question 15

What is the treatment paradigm

Answer 15

Steroids and RT ASAP
RT dose of 5400-5940 to T1 PG and FLAIR+ 1-2 cm (anatomically constrained) = CTV
PTV= CTV= 3 mm
Generally no TMZ
hyper and hypofx has not helped but can consider 44.8/16 fx or 39/13 fx

Question 16

What is the median survival of pediatric midline gliomas

Answer 16

9-12 months

Question 17

What is a LGG exophytic glioma

Answer 17

-A midline gioma arising from the 4th ventricle and not invading the brain stem
-Typically they are pilocytic astrocytomas
-After GTR, 10 year survival is > 75%

Question 18

What age group gets choroid plexus carcinomas/papillomas

Answer 18

70% of patients with CPCs are under the age of 2

Question 19

Where do choroid plexus carcinomas/papillomas occur in kids vs. adults

Answer 19

In kids they arise in the lateral ventricle
In adults, they arise in 4th ventricle

Question 20

What is the workup for patients for choroid plexus carcinomas/papillomas

Answer 20

CSF cytology
MRI brain and total spine

Question 21

Describe differences between choroid plexus carcinomas appear vs. papillomas on MRI

Answer 21

Papillomas- 60% are benign, WHO grade 1. Very homogenously contrast enhancing on MRI, have calcifications, appear as a well circumscribed mass within the lateral ventricle

Carcinomas- 33% present with distant mets
Heterogeneously contrast enhancing
may have hemorrhage, necrosis
usually show invasion of the brain parenchyma

Question 22

What is the treatment paradigm for choroid plexus carcinoma/papillomas

Answer 22

Max safe resection
Can be difficult because they are friable and vascular
Chemo can be used neoadjvuantly or embolization can be done prior to surgery
chemo used- ifosdamide, carboplatin, etoposide
RT indicated if over age of 3, CPC, recurrent tumor, CSF poisitve

Question 23

What is the 5 year OS for CPC vs. CPP

Answer 23

CPC- after GTR 80-100%; after STR- 65%
CPP-20-30%