The document discusses medulloblastoma, a type of brain tumor that occurs most often in children. It arises from primitive cells located in the cerebellum. Key points include that surgery is usually the first treatment, but radiation therapy plays a central role in improving survival. Treatment may involve craniospinal irradiation with a boost to the tumor site. Prognosis depends on factors like age and extent of disease. Long term side effects can include neurological and endocrine issues due to radiation therapy.

2. By : Dr.Mohammad Abu Ashour
Radiation Oncology Resident /RMS

3.  Posterior fossa contains hindbrain which
consists of cerebellum, pons and medulla.
 The cavity of hindbrain is fourth ventricle.
This is bounded in front by pons and medulla
and behind by cerebellum.
 The vermis separates two lateral lobes or
cerebellar hemspheres.

5.  Medulloblastoma ( 40 % )
 Ependymoma
 Astrocytoma
 Brainstem Glioma
 Metastasis

6. The name was given by Baily and Cushing 1925
 Medulloblastoma name is from:
 Medulla (Greek for marrow)
 Blast (Greek word for germ)
 Oma (Greek for tumor)
 means “tumor of primitive undeveloped cells
located inside the cerebellum”.

7.  20 % percent of pediatric CNS tumors, 40% of
all PF tumors.
 The second most common pediatric CNS
tumor after low-grade glioma
medulloblastoma.
 M:F = 2:1.
 Median age 5–6 year in children and 25 year
in adults.

8.  MB patients present with symptoms and signs
of:
 1. Increased intra cranial tension.
 2. Cerebellar dysfunction.

9.  Headache
 vomiting
 altered mental status
 Confusion
 Unsteady walking , ataxia
 Dizzness
 cranial nerve involvement
 Bony pains (bone metastsis)

10.  Medulloblastoma is WHO IV tumor of small
blue cell origin which arise from medullblast
?! cells mostly arise from vermis .
 WHO classification
 Classic 70%
 Desmoplastic /nodular MB 7%
 MB with extensive nodularity (MBEN) 3%
 Large cell /anaplastic variant 10-20%

11.  Gross picture soft , friable , extensive
necrosis
 Microscopic picture : highly cellular , dark
staining , round / .oval nuclei

13. occurs in infants
and is associated with a
good
prognosis.

17.  Direct invasion .
 CSF(30%).
 Extraneural (5%) Most common CNS tumor to
spread outside CNS
Hematogenous
MC sites are Long Bones and Ribs(10-15%) ,
LN(4-6%)

18.  H&P
 MRI of the brain (pre-op and post-op within
24–48 h after surgery)
 MRI of the spine to rule-out spread(MRI
within 14-21 days post surgery if not done
pre op )
 CSF cytology ( 14 – 21 days post op )
 Bilateral bone marrow biopsy
 Consider bone scan and CXR
 Baseline audiometry , IQ, TSH, CBC, and
growth measurements

23.  Chang system
 T1: <=3 cm
 T2: >3 cm
 T3a: > 3cm with extension into the aqueduct
of Sylvius and/or the foramen of Luschka
 T3b: > 3cm with unequivocal extension into
the brainstem
 T4: > 3cm with extension up past the
aqueduct of Sylvius and/or down past the
foramennmagnum

24.  M0 No metastases
 M1 Microscopic cells in CSF
 M2 Gross Nodular seeding in cerebellar,
cerebral subarachnoid space, third or lateral
ventricles
 M3 Gross Nodular seeding in spinal
subarachnoid space
 M4 Extraneuraxial metastasis

26.  1. Age at diagnosis
 2. Extent of disease
 3. Extent of resection
 4. Histology

27.  Standard risk: age >3 years and GTR/STR
with <1.5 cm residual and M0
 High risk: age <3 years or >1.5 cm residual,
or M+ , Diffuse Anaplastic type histology
Medulloblastoma (regardless of extent of
disease).
 66.6 % of patients are standard risk
 33.3% are high risk.

28.  Survival
 Standard-risk DFS 60–90%
 High-risk DFS 20–40%, increased to 50–85%
with adjuvant chemo

30.  “Surgery is usually the first step and mainstay
of treatment.” BUT Surgery alone is not
curative and the addition of radiotherapy has
significantly improved survival.
 Objective:
 Remove or Reduce as much of the tumor's
bulk as possible.
 Relieve ICT & local pressure effect ,i.e. V-P
Shunting.
 Tissue Diagnosis and staging – Biopsy

31.  Surgery is classified as:
 No evidence of residual tumor at surgery and
negative postoperativeimaging : Gross total
resection
 > 90% : Total or near total
 51 - 90% : Subtotal resection
 11 - 50% : Partial resection
 < 10% : Biopsy

32.  Edema in the brain
 Hematoma
 Aseptic meningitis
 Posterior fossa syndrome/ cerebellar mutism
syndrome:
15% of children
Difficulty in swallowing, truncal ataxia, mutism,
and, less often,respiratory failure.
noted after a 12 to 24 hour
often improve dramatically, sometimes over many
months after
surgery.

33.  Highly radio-sensitive.
 RT plays a central role.
Objective:
 To treat microscopic cancer cells / residual
tumor with the goal of reducing its size or
stopping its progression.
 Prevent or treat spread through CSF. Covering
the entire subarachnoid space is an essential
component in the management of
medulloblastoma.
 So We do Craniospinal irradiation (CSI).

34.  Nausea, vomiting
 neutropenia,thrombocytopenia
 Fatigue, headache,drowsiness
 Alopecia, mild dermitis
 Serous otitis media
 mucositis

35.  Spinal cord : radiation induced myelitis
 Brain :Radiation necrosis, Intellectual deficit
 Lens of eye :Cataract formation
 Retina :Radiation retinopathy
 Optic nerve: Optic neuritis
 Inner ear: Sensorineural hearing loss
 Hypothalamicpituitary Axis: Endocrinopathies
( hypothyroidism and decreased growth
hormone secretion)
 Secondary Malignancy.

36.  chemo-sensitive ( vincristine , PCV )
 Indication for CT :
 1. As Adjuvant with Surgery in child <3 yrs
to delay/avoid RT.
 2. In Recurrent /Progressive disease .
 3. In patients with Extra cranial mets .
 4. High risk Pt. to improve cure rates
 5. In avg. risk group to allow reduced RT
dose.

37.  TREATMENT RECOMMENDATIONS
 General management
 Hydrocephalus and increased ICP: steroids and
VP shunt before attempting resection
 Standard risk
 Surgical resection then CSI 23.4 Gy at 1.8-Gy/ fx
with PF boost to 54 Gy with concurrently with
vincristine then PCV chemo.
 High risk
 Surgical resection then post-op CSI 36–39 Gy at
1.8-Gy/fx, with entire PF and mets >1 cm
boosted to 54 Gy concurrently with vincristine
then PCV chemo.
 Infants
 <3-year old
 Surgery + intensive chemo. Reserve RT for
salvage

38.  –Patient Position: For CSI all patients are treated
in supine position .( historically prone position )
 –Immobilization devices: Head mask.
 –Anesthesia may required .
 – scan the brain and spine ( 3 mm and 5mm ),
which includes the entire head to the inferior
limit of the S4 vertebral body.

39.  Primary Gross Tumor Volume (GTV) The GTV
includes all gross residual tumor and/or the
tumor bed at the primary site based on the
initial pre-operative imaging examination
that defines the tissues initially involved with
disease anatomically and the post-operative
and pre-irradiation neuroimaging
examinations that identify residual disease
and/or the tumor bed. The GTV in most cases
will be a contracted or collapsed tumor bed.

40.  Metastatic Target Volume (MTV) : Overt
metastatic disease > 5mm in maximal
diameter will define a volume or volumes for
potential boost irradiation. The MTV will
include the contoured lesion(s) with a margin
of 0.5cm.

41.  •cranial CTV
 –Anteriorly : include the entire frontal lobe ,cribriform plate region and the
superior orbital tissue (but not the posterior globe ).
 –Inferiorly: at least 0.5 cm below the base of the skull at the foramen magnum.
 •Spine (CTV_SpI): the entire thecal sac.
 –Laterally : extend laterally on both sides to cover the recesses of the entire
vertebral bodies, with at least a 1 cm margin on either side
 –Superiorly : will be the junction with the whole brain field.
 –Inferiorly :should be placed after review of the spinal MRI. The border will be 2
cm below the termination of the subdural space. This will extend at least to the
inferior border of S2-S3 interspace, but may be as low as the inferior border of
S4.

42.  P.F BOOST : tumor bed with 1 cm margins .
PTV : CTV + 0.3-0.5 cm

43.  Brain : 2 lateral opposed fields .
 Spine : 1 posterior field if possible if not 2 .
 Gap : 0.5 cm

44.  In standard risk :
 Brain MRI - every 3 months, for the first 2
years Spinal MRI - every 6 months, for the
first 2 years;
 then Brain MRI every 6 months up to 3 years
and
MRI every year for 3 yrs.
 In high-risk :
 brain and spinal MRI - every 3 months for the
first 2 years then every 6 months.

45.  Relapses occur in nearly 75% of paediatric cases within 2
years.
 Sites•
Post. Fossa ( most common siteof relapse) , spinal cord .
 Diagnosed by neuroimaging;
 occasionally, clinical progression precedes neuroimaging
findings.
 Treatment at relapse:
 Localized brain recurrence: Surgery , radiation therapy
combined with various chemotherapy schedules.”
 Disseminated disease: Chemotherapy or best supportive
care
 including radiation.

46.  Evans et al. (1990) CCSG/RTOG – phase III:
233 patients with medulloblastoma
underwent surgery then randomized to
post-op RT vs. post-op chemo-RT followed
by chemo × 1 year. RT was CSI 35–40 Gy with
PF boost to 50–55 Gy + spinal mets to 50 Gy.
 Chemo was concurrent vincristine, adjuvant
vincristine, CCNU, and prednisone ×1 year.
Five-year OS 65% in both arms. Chemo
improved EFS in T3–4, M1–3 (46% for chemo-
RT vs. 0% for RT alone)

47.  Medulloblastoma is pediatric age group tumor.
 Raised ICT is the most common presentation.
 CT, MRI have important role in diagnosis and
treatment.
 Surgery is the primary modality of treatment .
 RT has central role in treatment.
 Infants pt treated with intent to avoid or delay
the RT.
 Long term neurological sequalae seen in CSI.