[ROQs] PEDS, Medulloblastoma, Ependymoma, Brainstem Glioma, Craniopharyngioma Flashcards
1
Q
What is the most common location(s) for an ependymoma?
A
Most to least common:
- Intracranial: ~95%
– Posterior fossa (infratentorial): 2/3
– Supratentorial: 1/3
- Spinal Cord: ~5%
2
Q
What is the most important prognostic factor for ependymomas?
A
Extent of resection
3
Q
What is the rate of 7-yr EFS for GTR vs. STR for ependymomas?
A
- GTR: 77%
- STR: 34%
4
Q
What is the rate of 7-yr OS for GTR vs. STR for ependymomas?
A
- GTR: 88%
- STR: 52%
5
Q
What are the most common malignancies in children (0-19 yrs old)?
A
- Leukemias
- CNS (20-25%)
– Highest death rate
6
Q
Which molecular subtype and features of ependymomas has the worst prognosis?
A
- Supratentorial ependymoma, ZFTA fusion-positive
– Previously RELA-fusion positive - Gain of chromosome 1q
– 5 yr EFS (47.4% vs. 82.8%, p=0.0013)
7
Q
Which molecular subtype of ependymomas has the best prognosis?
A
- Supratentorial ependymoma, YAP1-fusion positive.
8
Q
What is the general tx paradigm for the tx of ependymomas?
A
- Maximal Safe Resection: GTR a/w the greatest survival benefit
- f/b IFRT
- < 18 mos → CHT f/b 2nd look surgery if STR to delay RT in an infant
9
Q
What is the peak incidence age range for a dx of medulloblastoma?
A
5-9 yrs
10
Q
What is the typical location of Atypical Teratoid Rhabdoid Tumors (ATRT)?
A
Cerebellum: ~ 2/3 rd
11
Q
What % of newly dx medulloblastoma pts will have CSF dissemination at dx?
A
33%
12
Q
What locations within the cerebellum/posterior fossa are typical for medulloblastoma?
A
- Vermis, typically
- More lateralized in older pts
13
Q
What are the general dose and contouring guidelines for ependymomas?
A
- Per COG ACNS 0831
– Fuse both T1 post-gad and T2 pre and post-op MRIs to the planning CT
– GTV: Gross residual tumor and tumor bed based
– CTV: GTV + 5 mm (NOTE that prior protocols used 1 cm)
– Total Dose: 59.4 Gy / 33 fx
— Unless age < 18 mos and GTR, then treated to 54 Gy
14
Q
What is the open trial COG ACNS 0831 investigating?
A
- Phase Ill study of:
1. GTR of a differentiated, supratentorial ependymoma → Observation
2. STR → induction chemo → 2nd-look surgery → RT → chemotherapy
3. All others: RT f/b chemo vs. observation
15
Q
What is the most common cerebellar malignant tumor in children?
A
- Medulloblastoma
- ~20% of all brain tumors
16
Q
Is WNT subgroup of medulloblastoma fav. or unfav. and how does it affect tx recs?
A
- Favorable
- a/w Turcot Syndrome
- Does not affect tx recs
17
Q
What is the M staging for medulloblastoma?
A
- M0
- M1: Microscopic tumor cells in the CSF
- M2: Gross nodular seeding in the intracranial subarachnoid space or ventricular system distant from the primary site
- M3a - Gross nodular seeding in the spinal subarachnoid space with no evidence of
intracranial seeding. - M3b - Gross nodular seeding in the spinal subarachnoid space plus intracranial seeding.
- M4 - Extraneural metastasis.
18
Q
What is the long-term disease control for a craniopharyngioma tx w/ STR f/b adj. RT?
A
80-100%
19
Q
What is the rate of endocrinopathies for a craniopharyngioma tx w/ STR f/b adj. RT?
A
~20%
20
Q
Are craniopharyngiomas benign?
A
Yes! They are benign, locally destructive lesions
21
Q
What is the rate of endocrinopathies for a craniopharyngioma tx w/ GTR only?
A
~ 50%
22
Q
What is the rate of diabetes insipidus for a craniopharyngioma tx w/ GTR only?
A
~ 80-90%
23
Q
What is the rate of hypothalamic obesity for a craniopharyngioma tx w/ GTR only?
A
~ 50%
24
Q
What is the buzzword for the fluid that drains out of a craniopharyngioma?
A
Crankcase Oil
25
What is the rate of recurrence of craniopharyngiomas s/p GTR alone vs. STR alone?
- GTR: ~10% at 2 yrs, ~30% at 5 yrs
- STR: >75% at 6 mos!
-- RT is always recommended (min dose 54-55.8 Gy)
26
What are the two main WHO sub-types for craniopharyngiomas?
- Papillary
- Adamantinomatous
27
What is an average risk medulloblastoma pediatric patient?
- Avg. risk medulloblastoma
-- Incidence: 66%
-- ≥ 3 years old,
-- ≤1.5 cm2 residual
-- M0
-- Classic, or desmoplastic, or focal anaplastic histology
28
What are the different histologic variants of medulloblastoma?
- Classic
- Desmoplastic/nodular
- Desmoplastic with extensive nodularity
- Large cell
- Anaplastic
-- Desmoplastic variant has the best prognosis
- Anaplastic and large cells have the worst prognosis
29
What is the typical tx for an average-risk pediatric medulloblastoma patient?
Avg. risk medulloblastoma pt:
- CSI 23.4 Gy
- → ***IFRT* to 30.6 Gy boost** (54 Gy total) w/ conc. vincristine
- → PCV/Cyclov CHT (x9C q6 wks)
30
What is the CSI dose for an average-risk pediatric medulloblastoma patient who cannot receive concurrent vincristine 2/2 renal issues?
- 36 Gy
31
What was the 5-yr EFS in the POG8631/CCG 923, which randomized medulloblastoma pts to **23.4 Gy vs. 36 Gy CSI. w/o CHT** f/b posterior fossa boost to 54 Gy,
- 23.4 Gy: 67%
- 36 Gy: 52%
- p =0.008
32
How long does the tx of standard-risk medulloblastoma take?
~ 60 wks (~1 yr)
33
How do you define the IFRT volume for avg. risk medulloblastoma pt s/p CSI?
- Gross tumor + resection cavity
- 1.5 cm expansion excluding bone and tentorium
34
What are the presenting sx of medulloblastomas?
- Sx 2/2 posterior fossa mass:
-- Raised ICP
-- Headache
-- Vomiting
-- Diplopia
-- Head tilt
-- Gait ataxia
-- Behavioral changes
35
How often should you feather fields when treating w/ CSI?
- q 9 Gy
- Shift up and down by 0.5-1.0 cm to the field match points
36
What is a high-risk pediatric medulloblastoma patient?
- High-risk medulloblastoma
-- Incidence: 33%
-- < 3 yr old
-- STR > 1.5 cm2 residual
-- M+
-- Diffuse anaplastic histology
37
What is the management of supratentorial neuroepithelial tumor (previously, PNET (primitive neuroectodermal tumors))?
Same as Medulloblastoma:
- CSI 36 Gy
- → ***PF* + Met (>1 cm) to 19.8 Gy boost** (55.8 Gy tota) w/ conc. vincristine
- → PCV CHT
38
What is the typical tx for a high-risk pediatric medulloblastoma patient?
- CSI 36 Gy
- → ***PF* + Met (>1 cm) to 19.8 Gy boost** (54-55.8 Gy) w/ conc. vincristine
-- If discrete spots of disease within the spine, boost of 9 gy (45 Gy total)
-- If diffuse spine disease, a boost of 3.6 Gy (39.6 Gy)
- → PCV CHT
39
What are the sx of posterior fossa syndrome and when does it occur?
- Occurs w/i 1-2 days of posterior fossa tumor resection
- Incidence: ~ 22%
- Sx: SAME
-- **S**wallowing difficulty
-- **A**taxia
-- **M**utism
-- **E**motional lability
40
What are the classic borders of the posterior fossa boost after CSI?
- Borders:
-- Sup = Tentorium
-- Inf = C2-3 junction, through foramen magnum
-- Lat = Bony walls of the occiput and temporal bones
-- Ant = Posterior clinoids and anterior C1
-- Post = Cerebellar folia / Internal occipital protuberance
- Editing:
-- The pituitary should be blocked unless involved
-- the ENTIRE brainstem SHOULD BE INCLUDED
-- PTV: CTV + 3-5 mm (should extend anterior to posterior clinoid)
41
What were the purpose, pt population, and randomization of ACNS 0331?
- Purpose
-- Role of reduced dose CSI and reduced boost field in double randomization in pediatric patients w/ average-risk medulloblastoma (≥ 3 years old, ≤ 1.5 cm2 residual, M0)
- Pts
-- Aged 3-7
- Double-Randomization
-- 23.4 Gy vs. 18 Gy CSI
-- Entire posterior fossa boost vs. involved surgical field boost
-- Weekly vincristine for all
42
What were the results of ACNS 0331?
- Median follow-up: 9.3 years
- Surgical field boost vs. posterior fossa boost:
-- 5-yr OS: 85% vs 85% (NS)
-- 5-yr EFS: 82% vs 80% (NS)
-- 5-yr LR: 10% vs 8% (NS)
- CSI: 18 Gy vs. 23.4 Gy
-- 5-yr OS 78% vs. 86% (p<0.05)
-- 5-yr EFS: 71% vs. 83% (p<0.05)
-- 5-yr isolated distant failure: 13% vs. 8% (NS)
43
What is the age distribution for craniopharyngiomas?
- Bi-modal distribution, w/ peaks around
-- 5-15 yrs
-- 50-75 yrs
44
How often should you obtain MRIs for pts undergoing RT for craniopharyngiomas, and why?
- Weekly MRIs to determine if there is a reaccumulation of the cyst.
- CT scans, particularly cone-beam CT scans, are not sensitive enough to clearly define a reaccumulating cyst
45
For pts receiving CSI for medulloblastoma, what radiation dose and age predict the least impact on IQ?
- Low radiation dose
- Older age (≥ 7 yrs)
46
What is the initial tx of a newly-dx medulloblastoma?
- Maximal safe resection
- GTR results in a significantly improved prognosis
47
For medulloblastomas, when should RT start after resection?
3-4 weeks
48
What are the late-effect benefits of using protons vs. photons for CSI in children?
- Lower risk of:
-- Cardiac damage
-- Lung damage
-- Renal damage
-- Cochlear damage (ototoxicity)
-- 2ndary neoplasms
-- Endocrinopathies
49
How does using protons vs. photons for CSI in children affect adult height?
- Adult height is comparable b/w protons and photons
-- Vertebral bodies are normally included in the proton CSI volume to prevent asymmetric growth in children
50
Which embryonic remnant gives rise to cranipharyngiomas?
Rathke's pouch
- An invagination from the roof of the oral cavity that develops into the anterior portion of the pituitary gland (adenohypophysis)
- The neurohypophysis (posterior pituitary gland) descends from the developing brain
51
What is the optimal match level for cranial and spinal fields for CSI, especially when using photons?
- As low as possible
-- ~C5-6
-- Reduces dose to the mouth
-- Limited by shoulders blocking lateral fields
52
How can you distinguish atypical teratoid rhabdoid tumors (ATRT) from medulloblastomas?
- IHC for INI-1
-- A tumor suppressor gene on Ch 22
-- Lost in ~90% of ATRT
-- Intact in Medulloblastomas
53
What is the typical age of dx of ATRT, and what is the mainstay of tx?
- ≤ 3 yrs
- Surgical resection ± PORT
- CHT under investigation
54
In what order do pituitary hormones decrease after brain RT in children?
- In order:
-- GH
--- Endocrinologists check IGF-1 levels to infer GH levels
-- FSH/LH
-- TSH / ACTH
- *ADH is unaffected by RT
-- it is adversely affected by surgery, which can lead to DI*
55
What is the workup for ependymoma and medulloblastoma?
- Pre-op and post-op MR spine w/ contrast
- LP w/ cytology
-- 6-16% incidence of neuraxis dissemination
-- Post-op LP 10-14 days post-op to allow for surgical debris to clear
-- Pre-op LP prior to surgical intervention, but only if there is no evidence of elevated intracranial pressure or hydrocephalus by imaging and exam
56
What is the typical location of a medulloblastoma?
- Cerebellar vermis
57
Which CSF conduit is typically blocked by a medulloblastoma?
Cerebral Aqueduct (Aqueduct of Sylvius)
58
When should the staging Spine MRI be obtained for medulloblastoma?
- Pre-op
- 10-14 days post-op
-- Avoid immediate leftover from surgery (blood products, etc) from meddling the results
59
When should the post-op Brain MRI be obtained for Medulloblastoma?
- < 48 hrs after surgery
- To avoid confusing post-op changes, which start manifesting ≥ 48 hrs post-surgery from being mistaken fo residual tumor
60
What are the different molecular/genetic classifications of medulloblastoma and their associated prognosis?
- WNT: best prognosis
-- CTNNB1, stain for β catenin
- SHH: intermediate prognosis
-- PTCH1 (Gorlin syndrome), SMO, SUFU, MYCN amplification
- Group C/3: worst prognosis
-- MYC amplification and metastatic spread
- Group D/4: intermediate prognosis
-- isochrome 17q
## Footnote
WNT: Winning
Group 3 > W
61
Which medulloblastoma mutation is freq linked to the Gorlin syndrome?
SHH
62
Which cells give rise to ependymomas?
Ependymal cells lining the ventricles
63
Which cells give rise to meningiomas?
Arachnoid cap cells
64
What is the reason for significant hematologic toxicity in medulloblastoma pts receiving CSI?
Irradiation of significant amounts of bone marrow
65
How do you treat hematologic toxicity in medulloblastoma pts receiving CSI and boost?
- Stop CSI, switch to boost
- Resume CSI once leukopenias resolve
66
Is vincristine a/w cytopenias?
NO!
That’s why you don’t have to stop it when a pt develops cytopenias while undergoing CSI.
67
What is the prognosis of a child dx w/ DIPG?
- Uniformly poor prognosis
- Median survival after dx: 6-12 mos
68
What is the general tx paradigm for pineoblastoma?
- Similar to other high-risk CNS tumors
- Maximal safe resection
- CSI: 36 Gy
--Gross disease above spinal cord terminus: Boost of 9 Gy (45 Gy)
-- Gross disease below spinal cord terminus: Boost of 18 Gy (54 Gy)
-- Diffuse spinal disease; Boost to 3.6 Gy (39.6 Gy)
- Posterior fossa boost: 19.4 Gy
69
What are the CT simulation and RT field considerations for CSI?
- General:
-- Supine or prone
-- Deep sedation or general anesthesia for young children
-- Neck extended sufficiently to keep the mandible out of the exit beam of the spinal field
- Brain Fields:
-- Parallel opposed fields
-- Extend to > 1 cm beyond the scalp
-- Collimator rotated to match the divergence of the spinal field
- Spinal Field:
-- Single PA field.
-- Should cover 1-1.5 cm beyond the vertebral bodies laterally
- Posterior fossa boost
-- Supine or prone
70
What are the general targets for CSI?
- Whole-brain CTV1:
-- Ant: Frontal lobe, cribriform plate anteriorly, superior orbital tissue but not posterior globe
-- Inf: > 0.5 cm below the base of the skull at the foramen magnum
- Spine CTV1
-- Entire *thecal sac* using the spinal MRI to determine the inferior border, ~2 cm below the termination of the subdural space
- Limited target volume boost CTV boost:
-- GTV using preop MRI
-- CTV boost is GTV + 1.5 cm margin
-- Limit to bone or tentorial interface
71
What age cutoff is a/w the highest risk of endocrinopathies from RT?
≤ 10 yrs
