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Presented By: Dr. Vandana  Deptt. of Radiotherapy CSMMU, Lucknow
Introduction <ul><li>The origin of Medulloblastoma is from  medulla  ( Latin for marrow),  blastos  (Greek word for germ) ...
Origin <ul><li>A highly malignant primary brain tumor that originates in the cerebellum vermis or posterior fossa. </li></...
Anatomy <ul><li>Posterior fossa contains hindbrain which consists of cerebellum, pons and medulla. </li></ul><ul><li>The c...
CSF Pathways <ul><li>CSF is produced  by modified ependymal cells in choroid plexus </li></ul><ul><li>It circulates from l...
Epidemiology <ul><li>Overall account  ~ 7% all brain  tumors </li></ul><ul><li>10-20% of brain tumors in pediatric age  gr...
Adult vs. Paediatric Medulloblastoma Child Adult Usual age ~ 4 - 8 yrs Median age ~ 24 - 30 yrs Shorter clinical History (...
Natural History Arising in the midline cerebellar vermis (roof of the 4 th  ventricle) Grows into the 4 th  ventricle Fill...
Mode of Spread <ul><li>Contagiously-  </li></ul><ul><ul><ul><li>cerebellar peduncle  </li></ul></ul></ul><ul><ul><ul><li>F...
Pathological Features <ul><li>Highly cellular tumor </li></ul><ul><li>High N:C ratio </li></ul><ul><li>Cells arranged in t...
<ul><li>Classic Medulloblastoma:  densely  packed cells, hyperchromatic nuclei </li></ul><ul><li>Medulloblastoma with exte...
<ul><li>Large cell medulloblastoma:  Large nuclei, abundant cytoplasm. </li></ul><ul><li>These ‘large cells’ tend to mix w...
Chang Surgical classification 1969  T1 Tumour < 3 cm in diameter and limited to classic position in vermis, roof of fourth...
Clinical Features <ul><li>Raised ICT:  Due to obstructive or non communicating hydrocephalus </li></ul><ul><li>Pressure Sy...
<ul><li>Cerebellar Signs: </li></ul><ul><li>In children, tumor involve cerebellar vermis causes gait  ataxia. </li></ul><u...
Diagnostic Work up <ul><li>Detailed Clinical history:  Morning headaches, nausea, vomitting, confusion,  visual changes, u...
Confirmation of diagnosis <ul><li>NeuroRadiological examination </li></ul><ul><li>Biopsy </li></ul>Resection of tumor VP S...
Neuro Radiological examination CT finding <ul><li>Hyperattenuated, well-defined vermian cerebellar mass </li></ul><ul><li>...
MRI features : MRI is the gold standard. <ul><li>Iso- to- hypointense relative to adjacent cerebellar vermis (T1 images) <...
Fig:  ( B, ) non-contrast axial T1-weighted  (C,)  T2-weighted MR images; the solid portion of the tumor appears mildly hy...
Adult Medulloblastoma <ul><li>Poorly defined masses located in the cerebellar hemisphere. </li></ul><ul><li>Cyst like regi...
Spinal MRI <ul><li>Fig:  Sagittal and axial MRI, T1 weighted Gadolinium contrast enhancement  –  Medulloblastoma with meta...
Advantage of MRI over CT <ul><li>Highly sensitive </li></ul><ul><li>High resolution in diagnosing posterior fossa tumor be...
<ul><li>CSF examination:  Important for staging </li></ul><ul><ul><li>Lumber puncture:  most common method for obtaining C...
Risk Factor <ul><li>At diagnosis, 2/3 rd   of patients are standard risk and 1/3 are high risk. </li></ul><ul><li>Standard...
Treatment <ul><li>Medulloblastoma is well managed by multimodal  approach. </li></ul>
Surgery <ul><li>“ Surgery is usually the first step and mainstay of treatment.” </li></ul><ul><li>Objective: </li></ul><ul...
<ul><li>Complication </li></ul><ul><ul><li>Edema in the brain </li></ul></ul><ul><ul><li>Hematoma </li></ul></ul><ul><ul><...
Ventriculoperitoneal Shunt <ul><li>VP   shunting done for hydrocephalous reduction if repeated drainage fails to release s...
RADIOTHERAPY  <ul><li>Highly radio-sensitive. </li></ul><ul><li>RT plays a central role. </li></ul><ul><li>Objective:   </...
Cont… <ul><li>CSI is a very complex technique </li></ul><ul><li>Goal is to achieve uniform dosage throughout the subarachn...
<ul><li>Target Volume: </li></ul><ul><ul><li>Entire brain and its meningeal coverings with the CSF </li></ul></ul><ul><ul>...
<ul><li>Dose  </li></ul><ul><li>CSI (Phase I) </li></ul><ul><ul><li>30- 36 Gy in 18 - 21 # over 4 weeks to the cranium @ 1...
PLANNING STEPS <ul><li>Positioning </li></ul><ul><li>Immobilization </li></ul><ul><li>Simulation  </li></ul><ul><li>Field ...
Patient position  <ul><li>Prone (preferred):  </li></ul><ul><li>Supine:  </li></ul><ul><ul><li>More patient comfort. </li>...
Immobilization method <ul><li>Orfit cast for immobilization of the head, cervical spine & shoulder </li></ul><ul><li>Small...
Different RT techniques for CSI <ul><li>Initially entire CNS is irradiated at one stretch with a single field. Pt. is pron...
German Helmet Technique <ul><li>German Helmet Technique: </li></ul><ul><li>Field set so that beam flashes over entire head...
Field Arrangements <ul><li>Whole brain </li></ul><ul><ul><li>In the simulator, opposing lateral fields are applied to the ...
SPINAL FIELD  <ul><li>Laterally  - 1 cm margin beyond the pedicles, to cover the spinal cord and meninges along the nerve ...
Post fossa boost <ul><li>Volume includes entire Infratentorial compartment. </li></ul><ul><li>Field arrangement : </li></u...
TECHNIQUES OF MATCHING CS FIELDS <ul><li>Collimator/Couch rotation  </li></ul><ul><li>Half beam block  </li></ul><ul><li>A...
Collimator Couch rotation  <ul><li>Classically described technique. </li></ul><ul><li>Divergence of the spinal field into ...
Collimator rotation :  While treating cranial field rotate Collimator of lateral field so that its inferior border is para...
<ul><li>In order to avoid the overlap resulting from inf. Divergence of cranial field, rotate the couch towards the collim...
COUCH ROTATION Couch θ  = arc tan ( L2/2 x SAD ) For Co 60  SAD = 80 L2  ( Length of  cranial field) Cranial field SAD Zon...
Disadvantage of Couch Collimator rotation <ul><li>The lesser separation at the neck can  increase  the dose to the spinal ...
<ul><li>Conversely in case of the spinal cord the lower SSD will result in an  increased  dose. </li></ul><ul><li>Areas of...
Half Beam Blocking Actual Field Length Spinal field
Moving junction in CSI <ul><li>Feathering after every 5-7 fraction smoothes out any over or underdose over a longer segmen...
Aligning Spinal field <ul><li>Abutting fields : will result in  heterogenous dose to the spinal cord . </li></ul><ul><li>T...
Fixed or calculated gap spinal fields <ul><li>Gap calculation formula S=  ½ x L1(d/SSD1)+1/2xL2(d/SSD2) </li></ul>Cold Spo...
Double junction techniques <ul><li>The post field divided into two halves. </li></ul><ul><li>An overlapping segment is tre...
RADIATION TOXICITY <ul><li>ACUTE TOXICITY </li></ul><ul><li>Nausea, vomiting </li></ul><ul><li>neutropenia, thrombocytopen...
CHEMOTHERAPY <ul><li>chemo-sensitive  </li></ul><ul><li>Indication for  CT : </li></ul><ul><ul><li>As Adjuvant with Surger...
Chemotherapy regimen <ul><li>Single agent CCNU </li></ul><ul><ul><li>Lomustine 100-130 mg/m2 x 6 wks </li></ul></ul><ul><l...
Follow up <ul><li>In standard risk  : </li></ul><ul><li>Brain MRI - every 3 months, for the first 2 years </li></ul><ul><l...
Recurrence <ul><li>Relapses occur in nearly 75% of paediatric cases within 2 years. </li></ul><ul><li>Predicted by collins...
RECENT ADVANCES <ul><li>CSI followed by chemotherapy is the standard of care for both average and high-risk children ages ...
Ongoing Trials <ul><li>In average-risk disease, lowering of the craniospinal dosage to 18 Gy, conformal posterior fossa ra...
Summary <ul><li>Medulloblastoma is pediatric age group tumor. </li></ul><ul><li>Raised ICT is the most common presentation...
<ul><li>THANK YOU </li></ul>
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Diagnosis, Treatment & Management of Medulloblastoma

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Dr Vandana, cranio spinal irradiation, radiotherapy, medulloblastoma, cancer, radiation, treatment, diagnosis, management, natural history of medulloblastoma, signs & symptoms of medulloblastoma,
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  • medulloblastoma 09/30/11 Csi
  • Transcript of "Diagnosis, Treatment & Management of Medulloblastoma "

    1. 1. Presented By: Dr. Vandana Deptt. of Radiotherapy CSMMU, Lucknow
    2. 2. Introduction <ul><li>The origin of Medulloblastoma is from medulla ( Latin for marrow), blastos (Greek word for germ) and oma ( Greek for tumor); </li></ul><ul><li>means “tumor of primitive undeveloped cells located inside the cerebellum”. </li></ul><ul><li>Most common malignant primary brain tumor of child age group. </li></ul><ul><li>First described by Harvey Cushing and Percival Bailey in 1930. </li></ul><ul><li>Initially described as “ spongioblastoma cerebelli ” - a soft, suckable tumor usually arising in the vermis of cerebellum. </li></ul><ul><li>In 1925, changed name to medulloblastoma - from “medulloblast” - a hypothetical multipotent cell. </li></ul>
    3. 3. Origin <ul><li>A highly malignant primary brain tumor that originates in the cerebellum vermis or posterior fossa. </li></ul><ul><li>Arise in cerebellum and projects into 4 th ventricle. </li></ul><ul><li>Originate from embryonal cells k/a medulloblast of cerebellar stem cells. The exact cell of origin, or “medulloblast” has yet to be identified. </li></ul><ul><li>It is currently thought that it arises from Germinative neuroepithelial cells in the external granular layer of cerebellum. </li></ul>
    4. 4. Anatomy <ul><li>Posterior fossa contains hindbrain which consists of cerebellum, pons and medulla. </li></ul><ul><li>The cavity of hindbrain is fourth ventricle. This is bounded in front by pons and medulla and behind by cerebellum. </li></ul><ul><li>The vermis separates two lateral lobes or cerebellar hemspheres. </li></ul><ul><li>Because of the location of the fourth ventricle, ventral to the cerebellum, mass lesions or swelling of the cerebellum can cause obstructive hydrocepahalus. </li></ul>Relevant Neuroanatomy
    5. 5. CSF Pathways <ul><li>CSF is produced by modified ependymal cells in choroid plexus </li></ul><ul><li>It circulates from lateral ventricles into the third ventricle through the foramen of munro. </li></ul><ul><li>It then passes into the fourth ventricle through the narrow cerebral aqueduct. </li></ul><ul><li>From the fourth ventricle, it passes slowly through median aperture (foramen of magendie) and lateral foramina (foramen of luschka) and enters the subarachnoid space over brain and spinal cord. </li></ul><ul><li>It is reabsorbed into venous sinus blood via arachnoid granulations. </li></ul>Lateral Ventricle Foramen of Munro Third Ventricle Foramen of Luschka Foramen of Magendie Central canal of Spinal Cord Subarachnoid Space
    6. 6. Epidemiology <ul><li>Overall account ~ 7% all brain tumors </li></ul><ul><li>10-20% of brain tumors in pediatric age group </li></ul><ul><li>0.4%–1% of all adult central nervous system tumors </li></ul><ul><li>40% of tumors of the posterior fossa </li></ul><ul><li>Peak incidence at the age of 5 –6 yrs In children and 25 yrs in adults </li></ul><ul><li>Approximately 20% of Medulloblastoma present in infants younger than 2 years old; . </li></ul><ul><li>male : female (3:2) </li></ul>Figure: Distribution of pediatric central nervous system (CNS) tumors by location in the CNS and by tumor type.
    7. 7. Adult vs. Paediatric Medulloblastoma Child Adult Usual age ~ 4 - 8 yrs Median age ~ 24 - 30 yrs Shorter clinical History (~ 3 months) Longer history ( ~ 5 months) Classical type predominates Desmoplastic type relatively commoner Median cerebellar syndrome predominates Lateral cerebellar syndrome seen Biologically more agressive Biologically less aggressive Poorer resectability - median location Greater resectability - lateral location Higher surgical morbidity and mortality Lower surgical morbidity and mortality - impact of location and age Poorer RT tolerance Better RT tolerance Poorer long term survival Better long term survival
    8. 8. Natural History Arising in the midline cerebellar vermis (roof of the 4 th ventricle) Grows into the 4 th ventricle Fills into the 4 th ventricle Spread around the 4 th ventricle Invasion of ventricular floor Invasion of brain stem Invasion of brachium pontis CSF Spread Extra neural spread :Y oung age, males and diffuse subarachnoid disease
    9. 9. Mode of Spread <ul><li>Contagiously- </li></ul><ul><ul><ul><li>cerebellar peduncle </li></ul></ul></ul><ul><ul><ul><li>Floor of forth ventricle </li></ul></ul></ul><ul><ul><ul><li>Ant-brain stem </li></ul></ul></ul><ul><ul><ul><li>Inf –cervical spine </li></ul></ul></ul><ul><ul><ul><li>Sup- above tentorium </li></ul></ul></ul><ul><li>CSF(30%) – </li></ul><ul><ul><ul><li>Intracranially </li></ul></ul></ul><ul><ul><ul><li>Leptomeninges </li></ul></ul></ul><ul><ul><ul><li>Spinal cord </li></ul></ul></ul><ul><li>Extraneural (5%) Most common CNS tumor to spread </li></ul><ul><ul><ul><li>Hematogenous </li></ul></ul></ul><ul><ul><ul><li>MC sites are Long Bones and Ribs(10-15%) </li></ul></ul></ul><ul><ul><ul><li>LN(4-6%) </li></ul></ul></ul>
    10. 10. Pathological Features <ul><li>Highly cellular tumor </li></ul><ul><li>High N:C ratio </li></ul><ul><li>Cells arranged in typical Homer - Wright rosettes </li></ul><ul><li>Multiple histological subtypes </li></ul><ul><li>Classic medulloblastomas- 70-80% </li></ul><ul><li>Desmoplastic/nodular- 7% </li></ul><ul><li>Medulloblastoma with extensive nodularity (MBEN) - 3% </li></ul><ul><li>Anaplastic </li></ul><ul><li>Large Cell </li></ul>WHO classification - 2007 large cell / anaplastic (LCA) 10% to 22%.
    11. 11. <ul><li>Classic Medulloblastoma: densely packed cells, hyperchromatic nuclei </li></ul><ul><li>Medulloblastoma with extensive nodularity – (MBEN): occurs in infants and is associated with a good prognosis. </li></ul>classic medulloblastoma medulloblastoma with extensive nodularity
    12. 12. <ul><li>Large cell medulloblastoma: Large nuclei, abundant cytoplasm. </li></ul><ul><li>These ‘large cells’ tend to mix with cells with nuclear pleomorphism and k/a ‘anaplastic’ cells. </li></ul><ul><li>Diffuse anaplasia is associated with poor prognosis. </li></ul><ul><li>Desmoplastic/nodular: nodular, reticulin-free zones or ‘pale islands’. Surrounded by densely packed mitotically active cells. </li></ul>large cell medulloblastoma anaplastic medulloblastoma
    13. 13. Chang Surgical classification 1969 T1 Tumour < 3 cm in diameter and limited to classic position in vermis, roof of fourth ventricle, or cerebellar hemisphere T2 Tumour > 3 cm in diameter and further invading one adjacent structure or partially filling the fourth ventricle T3a Tumour further invading two adjacent structures or completely filling the fourth ventricle, with extensions into aqueduct or foramina of Magendie or Luschka with marked internal hydrocephalus T3b Tumour arising from the floor of fourth ventricle or brain stem and filling the fourth ventricle T4 Tumour penetrates aqueduct to involve third ventricle or midbrain or extends to cervical cord No N Stage M0 No metastases M1 Microscopic evidence of tumour cells in CSF. M2 Macroscopic metastases in cerebellar and/or cerebral subarachnoid space and/or supratentorial ventricular system M3 Macroscopic metastases to spinal subarachnoidal space M4 Metastases outside the central nervous system
    14. 14. Clinical Features <ul><li>Raised ICT: Due to obstructive or non communicating hydrocephalus </li></ul><ul><li>Pressure Syndrome: Nocturnal or morning head-ache, nausea and vomiting and papilledema. </li></ul><ul><li>Symptoms usually precede presentation by no more than 2 months. </li></ul><ul><li>Presenting symptoms are related to the age of the patient. </li></ul><ul><ul><li>infants with open cranial sutures, irritability, anorexia, failure to thrive, macrocephaly and setting sun sign. </li></ul></ul><ul><ul><li>The younger, nonverbal patient presents with behavioral changes, listlessness, irritability, vomiting, and decreased social interactions. </li></ul></ul><ul><ul><li>Older children and adults complain of headache, especially upon awakening in the morning. </li></ul></ul><ul><li>Decerebrate rigidity, head tilt, stiff neck s/o herniation </li></ul>
    15. 15. <ul><li>Cerebellar Signs: </li></ul><ul><li>In children, tumor involve cerebellar vermis causes gait ataxia. </li></ul><ul><li>In Adults, desmoplastic variant arises in cerebellar hemisphere causing ipsilateral dysmetria. </li></ul><ul><li>Worsening handwriting ,difficulty with hoping or running, slurring speech and hypotonia. </li></ul><ul><li>Neighbourhood syndrome : focal deficit due to pressure effect. </li></ul><ul><li>Brain stem : diplopia, 6th cranial nerve palsy, positional dizziness, nystagmus, tinnitus, hearing loss, facial sensory and motor loss . </li></ul><ul><li>Leptomeningeal dissemination: </li></ul><ul><li>Rarely the symptoms are present. </li></ul><ul><li>Patients can complain of radiculopathy </li></ul><ul><li>Bone mets- pain </li></ul><ul><li>Extra neural site - lymph node. </li></ul>
    16. 16. Diagnostic Work up <ul><li>Detailed Clinical history: Morning headaches, nausea, vomitting, confusion, visual changes, unsteady walking. </li></ul><ul><li>Physical examination: Gait, signs of raised ICT, double vision, stiff neck </li></ul><ul><ul><li>General examination </li></ul></ul><ul><ul><li>CNS examination </li></ul></ul><ul><ul><ul><li>Higher mental exam </li></ul></ul></ul><ul><ul><ul><li>Cerebeller exam </li></ul></ul></ul><ul><ul><ul><li>Sensory exam </li></ul></ul></ul><ul><ul><ul><li>Motor exam </li></ul></ul></ul><ul><ul><ul><li>Cranial N. exam </li></ul></ul></ul><ul><ul><li>Ophthalmoscopy examination for papilloedema </li></ul></ul>
    17. 17. Confirmation of diagnosis <ul><li>NeuroRadiological examination </li></ul><ul><li>Biopsy </li></ul>Resection of tumor VP Shunting + Biopsy High dose steroids + Neuro radiological examination Patient stable Medulloblastoma Histopathological examination Patient extremely somnolent
    18. 18. Neuro Radiological examination CT finding <ul><li>Hyperattenuated, well-defined vermian cerebellar mass </li></ul><ul><li>Surrounding vasogenic edema </li></ul><ul><li>Cyst formation </li></ul><ul><li>Evidence of hydrocephalus </li></ul>Fig: A, Axial noncontrast CT image demonstrates a large lobulated hyperdense round tumor ( arrow ) with an internal hypodense cavity. An ill-defined faintly hypodense band surrounding the hyperdense mass represents white matter edema.
    19. 19. MRI features : MRI is the gold standard. <ul><li>Iso- to- hypointense relative to adjacent cerebellar vermis (T1 images) </li></ul><ul><li>Iso intense to slightly Hyperintense on T2 weighted images </li></ul><ul><li>Homogeneous enhancement (but may be irregular and patchy) following contrast </li></ul><ul><li>MRI with contrast enhancement is very sensitive for detection of tumor spread, metastatic seeding in the cranial and spinal subarachnoid spaces. </li></ul>
    20. 20. Fig: ( B, ) non-contrast axial T1-weighted (C,) T2-weighted MR images; the solid portion of the tumor appears mildly hypointense on T1-weighting and mildly hyperintense on T2-weighting ( arrow ). Following intravenous gadolinium, an axial T1-weighted image ( D, ) demonstrates irregular patchy contrast enhancement of the solid areas of the tumor ( arrow ).
    21. 21. Adult Medulloblastoma <ul><li>Poorly defined masses located in the cerebellar hemisphere. </li></ul><ul><li>Cyst like regions are more commonly seen </li></ul>Fig: ( A,) Axial T2-weighted MR image demonstrates a poorly circumscribed mass with a heterogeneous signal pattern in the anteroinferior portion of the right cerebellar hemisphere. ( B,) After intravenous administration of gadolinium, the tumor demonstrates homogeneous contrast enhancement with well-circumscribed margins ( arrow ). Punctate intratumoral hypointensities represent enlarged vascular channels and/or focal calcifications.
    22. 22. Spinal MRI <ul><li>Fig: Sagittal and axial MRI, T1 weighted Gadolinium contrast enhancement – Medulloblastoma with metastatic spread to the meninges within the posterior fossa and with a large intramedullary deposit . </li></ul><ul><li>Most sensitive for spinal cord mets </li></ul><ul><li>Frequency of spinal seeding at diagnosis is 30-35%. </li></ul><ul><li>M.C.seen in the lumbosacral and thoracic areas and are best seen on post-contrast T1-weighted images. </li></ul><ul><li>MRI spine should be obtained whenever possible pre-operatively or else at least 2-3 weeks post-operatively. </li></ul>
    23. 23. Advantage of MRI over CT <ul><li>Highly sensitive </li></ul><ul><li>High resolution in diagnosing posterior fossa tumor because of high quality coronal images without artifacts, associated with beam hardening through bone in CT. </li></ul><ul><li>Sagittal images can be used in RT planning. </li></ul><ul><li>MRI better delineates tumor induced edema. </li></ul>
    24. 24. <ul><li>CSF examination: Important for staging </li></ul><ul><ul><li>Lumber puncture: most common method for obtaining CSF. </li></ul></ul><ul><ul><li>can’t be obtained pre-operatively because of raised ICT. More commonly obtained at 3 weeks post operatively. To avoid risk of misinterpretation due to post operative changes. </li></ul></ul><ul><li>Routine Investigations: Hemogram, KFT, LFT, Serum electrolyte, Chest X-ray, USG abdomen (Not mandatory) </li></ul><ul><li>Skeleton imaging : In case of Bone mets. </li></ul>
    25. 25. Risk Factor <ul><li>At diagnosis, 2/3 rd of patients are standard risk and 1/3 are high risk. </li></ul><ul><li>Standard Risk: 5yr. Survival is more than 80% </li></ul><ul><li>High Risk: 5 yr survival is 30-60% </li></ul><ul><li>M stage is a crucial staging component. </li></ul><ul><li>Several studies had shown that the T stage of the Chang's system did not correlate with survival- so replaced by the definition of the post operative residual tumor volume concept . </li></ul>Risk Factor Standard Risk High Risk Age > 3 yrs. < 3 yrs Residual Tumor < 1.5 cm 2 (Complete or near total resection) > 1.5 cm 2 (subtotal or biopsy) Mets M 0 M 1 - M 4
    26. 26. Treatment <ul><li>Medulloblastoma is well managed by multimodal approach. </li></ul>
    27. 27. Surgery <ul><li>“ Surgery is usually the first step and mainstay of treatment.” </li></ul><ul><li>Objective: </li></ul><ul><li>Remove or Reduce as much of the tumor's bulk as possible. </li></ul><ul><li>Relieve ICT & local pressure effect ,i.e. Shunting. </li></ul><ul><li>Tissue Diagnosis and staging – Biopsy. </li></ul><ul><li>Suboccipital Craniotomy </li></ul><ul><li>Surgery is classified as: </li></ul><ul><li>No evidence of residual tumor at surgery and negative postoperative imaging : Gross total resection </li></ul><ul><li>> 90% : Total or near total </li></ul><ul><li>51 - 90% : Subtotal resection </li></ul><ul><li>11 - 50% : Partial resection </li></ul><ul><li>< 10% : Biopsy </li></ul>
    28. 28. <ul><li>Complication </li></ul><ul><ul><li>Edema in the brain </li></ul></ul><ul><ul><li>Hematoma </li></ul></ul><ul><ul><li>Aseptic meningitis </li></ul></ul><ul><ul><li>Cervical instability </li></ul></ul><ul><ul><li>Posterior fossa syndrome/ cerebellar mutism syndrome: </li></ul></ul><ul><ul><ul><li>15% of children </li></ul></ul></ul><ul><ul><ul><li>Difficulty in swallowing, truncal ataxia, mutism, and, less often, respiratory failure </li></ul></ul></ul><ul><ul><ul><li>noted after a 12 to 24 hour </li></ul></ul></ul><ul><ul><ul><li>often improve dramatically, sometimes over many months after surgery. </li></ul></ul></ul><ul><li>Advantage: </li></ul><ul><ul><li>Longer recurrence-free interval (Gross total resection). “Exception is Brainstem involvement ”. </li></ul></ul><ul><ul><li>restores natural CSF pathways. </li></ul></ul>
    29. 29. Ventriculoperitoneal Shunt <ul><li>VP shunting done for hydrocephalous reduction if repeated drainage fails to release symptoms. </li></ul><ul><li>Complication: </li></ul><ul><li>Blood clot or bleeding in the brain </li></ul><ul><li>Brain swelling </li></ul><ul><li>The shunt may stop working and fluid will begin to build up in the brain again. </li></ul><ul><li>The shunt may become infected. </li></ul><ul><li>Infection in the brain </li></ul><ul><li>Damage to brain tissue </li></ul><ul><li>Seizures </li></ul><ul><li>Through VP shunt, tumor can spread. </li></ul>
    30. 30. RADIOTHERAPY <ul><li>Highly radio-sensitive. </li></ul><ul><li>RT plays a central role. </li></ul><ul><li>Objective: </li></ul><ul><li>To treat microscopic cancer cells / residual tumor with the goal of reducing its size or stopping its progression. </li></ul><ul><li>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 ). </li></ul>
    31. 31. Cont… <ul><li>CSI is a very complex technique </li></ul><ul><li>Goal is to achieve uniform dosage throughout the subarachnoid space, encompassing the entire intracranial vault and spinal canal. </li></ul><ul><li>Fundamental is </li></ul><ul><ul><li>the use of opposed lateral fields including the cranium and upper cervical spinal canal, </li></ul></ul><ul><ul><li>matching a posterior spinal field including the full spinal subarachnoid space with cranial field </li></ul></ul><ul><ul><li>in larger children, the upper posterior spinal field matching with a separate lower posterior spinal field </li></ul></ul>
    32. 32. <ul><li>Target Volume: </li></ul><ul><ul><li>Entire brain and its meningeal coverings with the CSF </li></ul></ul><ul><ul><li>Spinal cord and the leptomeninges with CSF </li></ul></ul><ul><ul><li>Posterior fossa – boost </li></ul></ul><ul><li>Energy </li></ul><ul><ul><li>4-6 MV linac or Co 60 </li></ul></ul><ul><li>Portals </li></ul><ul><ul><li>Whole Brain: Two parallel opposed lateral field. </li></ul></ul><ul><ul><li>Spine: Direct Posterior field </li></ul></ul><ul><li>Scheduling of radiotherapy: </li></ul><ul><ul><li>Starting time : within 28 days following surgery </li></ul></ul><ul><ul><li>Duration of treatment : 45 to 47 days </li></ul></ul>
    33. 33. <ul><li>Dose </li></ul><ul><li>CSI (Phase I) </li></ul><ul><ul><li>30- 36 Gy in 18 - 21 # over 4 weeks to the cranium @ 1.5-1.8 Gy per # </li></ul></ul><ul><ul><li>30-36 Gy in 18-21 # over 4 weeks to the spine @ 1.5-1.8 Gy per # </li></ul></ul><ul><li>Posterior fossa boost (Phase II) </li></ul><ul><ul><li>18-20 Gy in 10-11# over 2 weeks to the posterior fossa </li></ul></ul>
    34. 34. PLANNING STEPS <ul><li>Positioning </li></ul><ul><li>Immobilization </li></ul><ul><li>Simulation </li></ul><ul><li>Field arrangement </li></ul><ul><li>Matching of CSI </li></ul><ul><li>Aligning of spinal field </li></ul><ul><li>Implementation of plan </li></ul>
    35. 35. Patient position <ul><li>Prone (preferred): </li></ul><ul><li>Supine: </li></ul><ul><ul><li>More patient comfort. </li></ul></ul><ul><ul><li>I n-anaesthetic patient </li></ul></ul><ul><li>Head position </li></ul><ul><ul><li>Slightly extended and the shoulders pulled down </li></ul></ul><ul><ul><li>to avoid beam divergence into the mandibule & dentition. </li></ul></ul><ul><ul><li>Facilitates the use of a moving junction between the cephalad border of post. Spine field and the lower borders of cranial fields. </li></ul></ul><ul><li>Lumbar and Thoracic spine ll to couch. </li></ul>
    36. 36. Immobilization method <ul><li>Orfit cast for immobilization of the head, cervical spine & shoulder </li></ul><ul><li>Small children –inverted full body plaster cast with facial area open for access for anesthesia </li></ul><ul><li>Alpha cradle </li></ul><ul><li>Vacuum devices </li></ul>
    37. 37. Different RT techniques for CSI <ul><li>Initially entire CNS is irradiated at one stretch with a single field. Pt. is prone below a shielded screen on top of RT table. It is known as Patterson FARR technique. Co 60 source exposes the entire craniospinal axis at a focus distance of 125 c.m. </li></ul><ul><li>Moving Field technique: Table and pt. moves longitudinally in relation to a perpendicular Co 60 beam which is stationary at 50 cm focal skin distance. </li></ul><ul><li>Hockey Stick technique: Pt. prone with head turned to one side. </li></ul><ul><ul><li>Field at base of brain is defined by cribriform plate and is above both orbital cavities. </li></ul></ul><ul><ul><li>Include middle cranial fossa and to exclude orbit and lens. </li></ul></ul><ul><ul><li>Each side of head is treated on alternate days. </li></ul></ul>
    38. 38. German Helmet Technique <ul><li>German Helmet Technique: </li></ul><ul><li>Field set so that beam flashes over entire head in ant , post, & sup directions and only the caudal margin is defined by collimator by RT machine . </li></ul><ul><li>Caudal margin is set up so that it follows a line drawn from Eyebrow through the ext. auditory canal to the post aspect of the skull At C2-C3 jt. </li></ul><ul><li>Here we shield extra-Cranial structure in the subfrontal region,facial structures, teeth and lens. </li></ul>
    39. 39. Field Arrangements <ul><li>Whole brain </li></ul><ul><ul><li>In the simulator, opposing lateral fields are applied to the whole brain with a collimator rotation of 7-11 o to match the divergence of the direct posterior spinal field. </li></ul></ul><ul><li>SFOP guidelines- The recommended placement of block is: </li></ul><ul><ul><li>0.5 cm below the orbital roof . </li></ul></ul><ul><ul><li>1 cm below and 1 cm in front of the lower most portion of the temporal fossa . </li></ul></ul><ul><ul><li>1 cm away from the extreme edges of the calvaria. </li></ul></ul>In Medulloblastoma nearly 15-20% of recurrences occur at cribriform plate site which is attributed to overzealous shielding ,because of its proximity to ocular structure it often get shielded.
    40. 40. SPINAL FIELD <ul><li>Laterally - 1 cm margin beyond the pedicles, to cover the spinal cord and meninges along the nerve roots upto the spinal ganglia </li></ul><ul><li>Caudal -1 cm below the termination of the thecal sac i.e. L5 –S3. </li></ul><ul><li>2 spinal fields are used if the length is > 36 cm. </li></ul><ul><li>In Dorsal Region, block lat. Field to cover heart and lungs. </li></ul><ul><li>In Lumber Region, reduce field to spare BM and Gonads. </li></ul>SSD technique Gantry Angle = 0 degree IMP point is length and depth of spinal fields. Field of approx.4–6 cm wide box over the spinal cord/vertebral bodies extends from C2 –S2 .
    41. 41. Post fossa boost <ul><li>Volume includes entire Infratentorial compartment. </li></ul><ul><li>Field arrangement : </li></ul><ul><ul><li>Two lat opposing fields . </li></ul></ul><ul><li>SFOP Guidelines : </li></ul><ul><li>Ant -0.5 cm in front of clivus </li></ul><ul><li>Upper -1 cm above midpoint b/w line joining foramen magnum and the skull. </li></ul><ul><li>Post- ll to ant margin in air . </li></ul><ul><li>Lower – 1 cm below occipital foramen. </li></ul>
    42. 42. TECHNIQUES OF MATCHING CS FIELDS <ul><li>Collimator/Couch rotation </li></ul><ul><li>Half beam block </li></ul><ul><li>Asymetric jaws </li></ul><ul><li>Moving Junction technique </li></ul>
    43. 43. Collimator Couch rotation <ul><li>Classically described technique. </li></ul><ul><li>Divergence of the spinal field into the cranial field is overcome with collimator rotation </li></ul><ul><li>Divergence of the cranial fields into the spinal fields is overcome with couch rotation (rotated so that the foot end moves towards the gantry). </li></ul>
    44. 44. Collimator rotation : While treating cranial field rotate Collimator of lateral field so that its inferior border is parallel to divergence of sup. Aspect of spinal field . θ Collimator rotation allows cranial field to match spinal field divergence Coll θ = arc tan ( L1 /2 x SSD ) For Co 60 SSD = 80 Zone of overlap of spinal field if collimator rotation is not applied in cranial field SSD L1
    45. 45. <ul><li>In order to avoid the overlap resulting from inf. Divergence of cranial field, rotate the couch towards the collimator so that fields margins of two fields become parallel. </li></ul><ul><li>Degree of couch rotation depends upon the length of lateral cranial fields and SAD </li></ul><ul><li>Θ couch = arc tan </li></ul><ul><li>(1/2 x L2 /SAD) </li></ul><ul><li>L2 = Cranial field length </li></ul>COUCH ROTATION Fig: Rotation of the couch toward the gantry is necessary to match the caudal margin of the lateral cranial fields with the cephalad margin of the posterior spinal field. 
    46. 46. COUCH ROTATION Couch θ = arc tan ( L2/2 x SAD ) For Co 60 SAD = 80 L2 ( Length of cranial field) Cranial field SAD Zone of overlap Spinal field Couch rotation during treatment of cranial field θ
    47. 47. Disadvantage of Couch Collimator rotation <ul><li>The lesser separation at the neck can increase the dose to the spinal cord. </li></ul><ul><li>Due to the couch rotation the cranial portions of the skull can move away and get treated a greater SSD (resulting in under dosage ) </li></ul>
    48. 48. <ul><li>Conversely in case of the spinal cord the lower SSD will result in an increased dose. </li></ul><ul><li>Areas of the opposite lower temporal lobe can get lower dose if customized blocks are used - lower border of the cranial fields need to be more generous. </li></ul>Figure: This figure illustrates a potential complication of the craniospinal setup. A couch angle on the lateral cranial fields can cause the contralateral temporal lobe to be underdosed
    49. 49. Half Beam Blocking Actual Field Length Spinal field
    50. 50. Moving junction in CSI <ul><li>Feathering after every 5-7 fraction smoothes out any over or underdose over a longer segment of cord . </li></ul><ul><li>Usually shifted by 1-2cm at each shift . </li></ul><ul><li>Either in cranial or caudal direction. </li></ul><ul><li>Lower border of sup. Spinal field & sup. Border of inf. Spinal field are also shifted superiorly , maintaining the calculated gap b/w them. </li></ul>“ Feathering” refers to movement of the junction of the two fields across the treatment length.
    51. 51. Aligning Spinal field <ul><li>Abutting fields : will result in heterogenous dose to the spinal cord . </li></ul><ul><li>To overcome this various techniques are available </li></ul><ul><ul><li>Gap technique </li></ul></ul><ul><ul><li>Double junction technique </li></ul></ul><ul><ul><li>Moving junction technique </li></ul></ul>
    52. 52. Fixed or calculated gap spinal fields <ul><li>Gap calculation formula S= ½ x L1(d/SSD1)+1/2xL2(d/SSD2) </li></ul>Cold Spot Hot Spot SSD 2 SSD 1 L2 S L1
    53. 53. Double junction techniques <ul><li>The post field divided into two halves. </li></ul><ul><li>An overlapping segment is treated with two diff. fields on alternate days. </li></ul><ul><li>The junction is therefore automatically feathered on alternate days </li></ul>Upper Spine Lower Spine Day of Planning Upper Spine Lower Spine Day 1 : The upper spinal field is shortened Upper Spine Lower Spine Day 2: The lower spinal field is shortened Junction on D 1 Junction on D 2
    54. 54. RADIATION TOXICITY <ul><li>ACUTE TOXICITY </li></ul><ul><li>Nausea, vomiting </li></ul><ul><li>neutropenia, thrombocytopenia </li></ul><ul><li>Fatigue, headache, drowsiness </li></ul><ul><li>Alopecia, mild dermitis </li></ul><ul><li>Serous otitis media </li></ul><ul><li>mucositis, oesophagitis (exit dose from spinal cord) </li></ul>LATE TOXICITY Spinal cord Chronic progressive myelitis Brain Radiation necrosis Intellectual deficit Lens of eye Cataract formation Retina Radiation retinopathy Optic nerve Optic neuritis Inner ear Sensorineural hearing loss  Hypothalamic-pituitary axis Endocrinopathies ( hypothyroidism and decreased growth hormone secretion) Secondary Malignancy
    55. 55. CHEMOTHERAPY <ul><li>chemo-sensitive </li></ul><ul><li>Indication for CT : </li></ul><ul><ul><li>As Adjuvant with Surgery in child <3 yrs to delay/avoid RT. </li></ul></ul><ul><ul><li>In Recurrent /Progressive disease . </li></ul></ul><ul><ul><li>In patients with Extra cranial mets . </li></ul></ul><ul><ul><li>High risk Pt. to improve cure rates </li></ul></ul><ul><ul><li>In avg. risk group to allow reduced RT dose. </li></ul></ul>
    56. 56. Chemotherapy regimen <ul><li>Single agent CCNU </li></ul><ul><ul><li>Lomustine 100-130 mg/m2 x 6 wks </li></ul></ul><ul><li>PCV </li></ul><ul><ul><li>Procarbazine 60-75 mg/m2 PO D18-21 </li></ul></ul><ul><ul><li>CCNU 110-130 mg/m2 PO D1 </li></ul></ul><ul><ul><li>Vincristine 1.4mg/m2 IV D8 &D29 </li></ul></ul><ul><li>Cisplatin & Etoposide </li></ul><ul><ul><li>Cisplatin 30mg/m2 IV D1-D3 </li></ul></ul><ul><ul><li>Etoposide 100 mg/m2 IV D1-D3 </li></ul></ul><ul><li>PCV (Most commonly used) </li></ul><ul><ul><li>CCNU 75 mg/m2 </li></ul></ul><ul><ul><li>Cisplatin 75 mg/ m2 </li></ul></ul><ul><ul><li>Vincristine 1.5 mg/m2 </li></ul></ul><ul><li>8 in 1 Regimen: </li></ul><ul><ul><li>MethylPDN 300 mg/m2 </li></ul></ul><ul><ul><li>Vincristine 1.5 mg/m2 </li></ul></ul><ul><ul><li>CCNU 75 mg/m2 </li></ul></ul><ul><ul><li>Procarbazine 75 mg/m2 </li></ul></ul><ul><ul><li>Hydroxyurea 1500 mg/m2 </li></ul></ul><ul><ul><li>Cisplatin 60 mg/m2 </li></ul></ul><ul><ul><li>Cytarabine 300 mg/m2 </li></ul></ul><ul><ul><li>Endoxan 300 mg / m2 </li></ul></ul><ul><li>CVP x 6 weekly </li></ul><ul><ul><li>CCNU 75 mg/m2 D1 </li></ul></ul><ul><ul><li>Vincristine 1.5 mg/m2 wklyx 3wks </li></ul></ul><ul><ul><li>Prednisolone 40 mg / m2 x 14 days </li></ul></ul>
    57. 57. Follow up <ul><li>In standard risk : </li></ul><ul><li>Brain MRI - every 3 months, for the first 2 years </li></ul><ul><li>Spinal MRI - every 6 months, for the first 2 years; </li></ul><ul><li> then Brain MRI every 6 months up to 3 years and </li></ul><ul><li>spinal MRI every year for 3 yrs. </li></ul><ul><li>In high-risk : </li></ul><ul><li>brain and spinal MRI - every 3 months for the first 2 years then every 6 months. </li></ul>
    58. 58. Recurrence <ul><li>Relapses occur in nearly 75% of paediatric cases within 2 years. </li></ul><ul><li>Predicted by collins rule of recurrence=age at diagnosis +9month </li></ul><ul><li>Sites </li></ul><ul><ul><li>Post. Fossa </li></ul></ul><ul><ul><li>supratentorial region including cribriform plate </li></ul></ul><ul><ul><li>spinal cord </li></ul></ul><ul><ul><li>ventricular walls </li></ul></ul><ul><li>Diagnosed by neuroimaging; </li></ul><ul><li>occasionally, clinical progression precedes neuroimaging findings. </li></ul><ul><li>Treatment at relapse: </li></ul><ul><li>Localized brain recurrence: Surgery  “ radiation therapy combined with various chemotherapy schedules.” </li></ul><ul><li>Disseminated disease: Chemotherapy or best supportive care including radiation. </li></ul>
    59. 59. RECENT ADVANCES <ul><li>CSI followed by chemotherapy is the standard of care for both average and high-risk children ages 3 and older </li></ul><ul><li>Current standard approach:Standard risk: Surgical resection  CSI 23.4 Gy at 1.8-Gy/fx with PF boost to 54 Gy with concurrent vincristine  PCV chemo. DFS ~80% </li></ul><ul><li>High risk: Surgical resection  post-op CSI 36–39 Gy at 1.8-Gy/fx, with entire PF and mets >1 cm boosted to 54 Gy with concurrent vincristine  PCV chemo. DFS ~60% </li></ul><ul><li>Infants<3-year old: Surgery  intensive chemo. Reserve RT for salvage </li></ul><ul><li>Contemporary CSI treatment & planning approach uses MRI and CT simulations (3D RTP). </li></ul><ul><li>Posterior boost also benefits from 3D-RTP and the use of highly-conformal 3D-CRT or IMRT techniques. </li></ul>
    60. 60. Ongoing Trials <ul><li>In average-risk disease, lowering of the craniospinal dosage to 18 Gy, conformal posterior fossa radiotherapy to the tumor volume and intensification of chemotherapy with autologous peripheral blood stem cell support. </li></ul><ul><li>Use of Proton in treatment to reduce exit dose. </li></ul><ul><li>The current SIOP (PNET 4) and UK-CCSG (CNS 2001) are addressing hyperfractionated and accelerated hyperfractionated delivery, respectively, in standard-risk </li></ul>
    61. 61. Summary <ul><li>Medulloblastoma is pediatric age group tumor. </li></ul><ul><li>Raised ICT is the most common presentation. </li></ul><ul><li>CT, MRI have important role in diagnosis and treatment. </li></ul><ul><li>Surgery is the primary modality of treatment . </li></ul><ul><li>RT has central role in treatment. </li></ul><ul><li>Standard risk: </li></ul><ul><ul><li>surgery  CranioSpinal Radiation or </li></ul></ul><ul><ul><li>concurrent chemo RT followed by post radiation chemotherapy. </li></ul></ul><ul><li>High risk: CranioSpinal radiation and post RT chemotherapy. </li></ul><ul><li>Infants pt treated with intent to avoid or delay the RT. </li></ul><ul><li>Long term neurological sequalae seen in CSI. </li></ul>
    62. 62. <ul><li>THANK YOU </li></ul>
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