Central nervous system Flashcards
glioma radiation dose grade II
grade II: ctv 54= gtv +15mm
45 gray 1.8 gray per fraction
9gray 1.8 gray per fraction
glioma high grade, grade 4 dose
ctv 50= 50 gray 25 fraction 5 week| ctv 60=10 gray 5 fraciton 1 week
CSI standard risk dose medulloblastoma
Standard risk: medulloblastoma
(classic, desmoplastic, MBEN , chang stage M0), </1.5cm of residual microscopic disease, no MYC or MYCN gene amplification)
phase 1
23.4 gy 1.8gy/fx 13 fraction in two and half wk
phase II
30.6 gray in 17 fraction total for 54 gray with ccrt vincristine 1.8 gray/fx
csi:high risk medulloblastoma dose
Criteria: (medulloblastoma: large cell or anaplastic histology, Chang stage M1-3{metastases in CSF, intracranially or in the sub arachnoid space}, >1.5cm2 or residual disease, MYC or MYCN gene amplification.
Phase 1:
M0/M1: 36 gy in 20 fraction given in four weeks
M2-3: 39.6 gy in 22 fractions given in four and a half weeks
Phase 2: tumor bed boost:
Total dose of 54-55.8 gy in 30-31 fractions given in six weeks
ependymoma radiation dose
54gy/30 fraction 1.8gy 6wks
cns lymphoma rt dose
whole brain 40gy 20 fracitonor 45 gy 25 daily fraction wtih chemotherapy MTXcombined with rituximab or ritu+tmz
medulloblastoma type
Medulloblastoma, molecularly defined
medulloblastoma, WNT activated
medulloblastoma, SHH activated and TP53 -wildtype
medulloblastoma, SHH activated and TP53 mutant
medulloblastoma, non WNT/non SHH
medulloblastoma histological type
WHO classification medulloblastoma 2021
a. Medulloblastoma histologically defined (classic, desmoplastic, extensive nodularity, large
cell/anaplastic, NOS; are now in 1 section)
Risk factor for cns tumor
history of radiation exposure
HIV,EBVNF1, P53, MEN1, NF2chemical: rubber compound, polyvinyl chloride, polycyclic hydrocarbon
CSI complication
acute
* GIT toxicity,
* dysphagia,
* odynophagia,
* weight loss,
* myelosuppression
late
* memory deficit
* hearing problem
* growth problem
High propensity for csf spred
Medulloblastoma
Pnet
Cns lymphoma
Prognostic factors
Prognostic Factors
Adverse Prognostic factor
1. Pathologic grade
2. Patient age
3. Overall clinical condition/Comorbidity
Better prognosis
1.IDH1 mutation
2. LOH in chromosome
3. IP & 19q in anaplasticoligodendroglioma
High risk factors for glioma
Idh mutation1p/19q deletionsAge>40yrsSize >6cmFocal neurological deficit
Common adult primary CNS tumor
meningiomas 30-35%
GBM 20%
pituitarynerve sheath tumor 10%
low grade glioma 5%
anaplastic astrocytoma <5%
primary cns lymphoma <5%
Common children CNS tumor
pilocytic astrocytoma 20%
malignant glioma/GBM 15%
medulloblastoma 15%
pituitary 5-10%
ependymoma 5-10%
optic nerve glioma <5%```
perinauds syndrome
paralysis of upward gaze psudo argyll robertson pupilconvergence retraction nystagmuscolliers sign sun setting sign
ependymoma management
spinal cord: maximal safe resection, if str give adj rt 50.4 graygrade 2/3: maximal safe resectionif spinal mri/csf +ve: csi 30-36gy+focal boost 54-60gy for local disease and 45gy for spine
differential diagnosis of posterior fossa mass
medulloblastoma
ependymoma
astrocytoma and metastasis
poor prognositic factor for medulloblastoma
male age <5 years
M1 disease
survival rate of medulloblastoma
standard risk DFS 60-90%| high risk: 20-40% increased to upto 50-85% with adjuvant chemo
Acute side of RT in CNS
Acute:
Hair:
Alopecia: alopecia starts at 7th day
Mucosa:
Erythema Edema Patchy mucositis Confluent mucositis
Eye:
Early:conjuntivitis Decreased tear drops Infection
Late:
necrosis in retina
Dry eye
Cataract
Optic nerve and optic chiasma damage at >50 gy
CNS:
Acute:
effect depends on edema, dose, site etc
Acute: within 6 weeks-
Pretreatment deficit worsens due to peritumoral edema-
Fatigue,
headache,
drowsiness-
Mild dermatitis-
Nausea, vomitting, more in post fossa brain irradiation-
Otitis externa-
Mucositis,
esophagitis due to exit dose
nazir sir
obliterating end arteritis
direct damage to nerve cell, blood cell, glial cell
narrowing of small blood vessel
Sub acute side effect of RT in CNS
Sub acute
That develop during 6 week to 6 months.due to changes in capillary permeability and well as transient demyelination due to damage to oligodendroglial cells-
Headache-
Somnolence-
Fatigability-
Deterioration of preexisting deficits- The phenomenon of psuedo progression fits within the subacute toxicity time frame
Late side effect of RT in brain:
Late sequale:
* 6 months to many years-
* Irreversible progressive nerve injury due to demyelination-
* Vascular injury necrosis-
* Radiation induced neuro cognitive damage
* Radiation necrosis: upto 3 years (differentiate by PET, MRS)-
* Diffuse leuko encephalopathy (CT+RT more common)-High tone hearing loss-
* Optic chiasm,
* nerve injury (>54 gy)-
* Hormone insufficiency (20gy)
* Spinal cord: L’Hermittes sign:
Nazir sir
moya moya syndrome
Indication of SRS
Clinical indication:
• SRS for single brain metastases:
o Dose <2cm is 24 gy, <2-3 cm is 18Gy, >3-4 cm is 15Gy
• Acoustic neuroma
• Pituitary adenoma
o Nonfunctioning adenoma 12-20gy, functioning adenoma 15-30gy
• Skull based meningioma
o 12-14 gy
• Arteriovenous malformation and cavernous hemangioma
o Dose tumor size <4cm is 20-25 Gy
• Trigeminal neuralgia
o Dose 70-90 gy
• Parkinson disease
Name some malignancies where CSRT is required
- medulloblastoma: average, high risk
- Ependymoma
- Pineoblastoma
- Primary cns lymphoma with leptomeningeal involvement
- Choroid plexus carcinoma with spinal metastatis
- Supratentorial PNET
- Intracranial germ cell tumor (Germinoma)
- Leukemia/ lymphoma (with CNS involvement)
What is suggestive of a malignant tumor on MR spectroscopy?
Show Answer
Increased choline (cell membrane marker), low creatine (energy metabolite), and low N-acetyl-aspartate (a neuronal marker) are suggestive of malignancy on MR spectroscopy.
Classification of glial tumor
Gr1: pilocytic astrocytoma
Gr2: diffuse astrocytoma, gemistrocytic astrocytoma
Gr3: anaplasticvatrocytoma
Gr4: GBM
What are the 5 negative prognostic factors for LGG as determined by EORTC 22844 and 22845? Pignatti criteria
Show Answer
Negative prognostic factors per the EORTC index:
1. Age>40yrs
2. Astrocytomahistology
3. Tumors ≥6 cm
4. Tumors crossing midline
5. Preopneurologicdeficits
(Pignatti F et al., JCO 2002)
Median survival for AA and GBM
Aa: 3yrs
Gbm: 14 mos
Name some supratentorial tumor
Glial tumor: low grade: astrocytoma
GBM
anaplastic astrocytoma
meningioma
oligodendroglioma
CNS lymphoma
Name some infratentorial tumor
brain tumor located in cerebellum and brainstem, fourth ventricle
-medulloblastoma
-craniopharyngioma
choroid plexus papilloma
ependymoma
PNET etc
Molecular marker affecting CNS
IDH 1/2 mutation
1P/19Q codeletion
TP53 mutation
ATRX mutation
TERT mutation
