Posterior Fossa Tumors (Peds)

Front 1

what percentage of childhood brain tumors arise in posterior fossa?

Back 1

nearly 50%

Front 2

Most common types of childhood posterior fossa brain tumors?

Back 2

medulloblastoma, low-grade astrocytomas of the cerebellum, brainstem gliomas, and ependymomas

Front 3

What is the most common malignant brain tumor in children and adolescents?

Back 3

medulloblastoma

Front 4

Medulloblastomas account for what percentage of pediatric brain tumors?

Back 4

20%

Front 5

most common histology for peds CNS?

Back 5

astrocytoma

Front 6

What tumors are considered PNETs?

Back 6

medulloblastoma, pineoblastoma, and supratentorial PNETs

Front 7

Medulloblastomas are by definition located where?

Back 7

posterior fossa

Front 8

Risk stratefication in medullos?

Back 8

average and high risk groups

Front 9

Medulloblastoma is the only PNET that gives less than what dose for certain risk groups?

Back 9

<36 Gy

Front 10

in medullos, everyone older than 3 years gets what?

Back 10

CSI

Front 11

Overall treatment paradigm in medullo?

Back 11

1st: surgery
2nd: RT +/- chemo
3rd: chemo

Front 12

Most common symptoms in medullo?

Back 12

70% vomiting (from ICP)
60% headache (from ICP)
40% ataxia
40% nausea
usually < 3 months of symptoms

Front 13

Initial evaluation for post fossa mass?

Back 13

CT or MRI. LP prior to surgery is almost never done (only if no hydrocephalus)

Front 14

Medulloblastoma M:F ratio?

Back 14

2:1

Front 15

Medullo median age at dx?

Back 15

7 years old

Front 16

what percentage of medullos present with subarachnoid dissemination?

Back 16

25%

Front 17

what percentage of medullos have gad enhancement at time of dx?

Back 17

15%

Front 18

What percentage at dx have a positive LP as the only sign of mets?

Back 18

<5% (usually the MRI will show enhancement)

Front 19

Post-op staging for medullo?

Back 19

MRI within 24 hours, lumbar MRI with LP 10-14 days postop.

Front 20

further work-up in advanced disease?

Back 20

bone scan, CXR, bone marrow bx

Front 21

Change staging system? (medullo)

Back 21

T staging: no longer used.
M staging:
M0 no mets
M1 positive CSF
M2 intracranial tumor beyond primary site
M3 gross nodular seeding in the spinal SA space
M4 mets outside the CSA (very rare)

Front 22

What is the most important predictor of survival in medulloblastoma?

Back 22

M stage

Front 23

medullo: need to start radiation within how many days of surgery?

Back 23

30

Front 24

medullo: what is 5 year OS for GTR and SRT respectively?

Back 24

GTR 80%
STR 40%

Front 25

What percentage of medulloblastomas undergo GTR at time of diagnosis?

Back 25

>90%

Front 26

What is considered the "posterior fossa syndrome?"

Back 26

mutism, truncal ataxia, and emotional lability

Front 27

What labs do we need to monitor during RT for medullo?

Back 27

ANC and plts

Front 28

In medullo, who gets chemo?

Back 28

everyone (both standard and high risk), also used to delay RT in kids <3

Front 29

What patients with medullo are considered standard risk?

Back 29

must fulfill all the following:
> 3 years old
GTR or STR with <1.5cm2 residual
M0

Front 30

Treatment of standard risk medullo?

Back 30

-monitor ANC and plts
- chemo (vincristine)
-CSI 23.4 Gy (consider 18 for kids 3-8, we have single institution data to support this (goldwein and jakacki))
-posterior fossa boost to 54 Gy (consider involved field on study, also have single institution data (st. jude and MSKCC))
-Adjuvant chemo (VCR, CDDP, cyclophosphamide (has replaced CCNU as standard in maintenance)