General
- MDT discussion
- Maximal safe resection + craniospinal RT + “sandwich” chemotherapy
- Postop MRI <48hrs + LP >10days postop for staging
Manage of acute hydrocephalus
- Srinivasan 2016: Following resection, between 10 and 40% of the patients have hydrocephalus requiring CSF diversion
- Higher in high risk groups
- Use modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) for preoperative prediction
Surgery
- Debulking of the primary tumour → Chemo + Radio depending on high or low risk
- Aim
- Diagnosis: establish histological, and molecular subtype
- Maximal safe resection
- More important to Chang stage M0 tumours
- Better to leave residue than to cause neurological deficit
- Brainstem decompression
- To reduce hydrocephalus
- Approach
- Surgical adjuncts
- Intra-operative monitoring
- Intra-operative MRI
- Complication
- Posterior fossa syndrome
- 20%
- Associated with poor neurological and cognitive outcomes
- Postop risk stratification
- Chang staging (pre-CT era) → COG since 1990s
- Chang surgical classification 1969
Stage | Description |
T1 | Tumour <3cm in diameter and limited to classic position in vermis, roof of fourth ventricle, or cerebellar hemisphere |
T2 | Tumour >3cm 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 extension 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 | ㅤ |
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 |
- Surgery
- Prognostic value of medulloblastoma extent of resection after accounting for molecular subgroup: a retrospective integrated clinical and molecular analysis - PubMed
- The prognostic benefit of increased extent of resection for patients with medulloblastoma is attenuated after molecular subgroup affiliation is taken into account.
- Although maximum safe surgical resection should remain the standard of care, surgical removal of small residual portions of medulloblastoma is not recommended when the likelihood of neurological morbidity is high because there is no definitive benefit to gross total resection compared with near-total resection.
Chemo and Radiotherapy
- Based on CCLG guidelines (Trial procedure from Gajjar 2006)
Standard risk
- Criteria
- Residual tumour < 1.5 cm² AND
- No Metastases on MRI AND
- CSF Negative for Tumour Cells AND
- Histology
- Classic
- MBEN
- Desmoplastic
- Molecular risk
- WNT in patient < 16 yrs have good prognosis
- Treatment
- All children
- Concurrent chemotherapy once weekly
- “PACKER” regime, consisting of cisplatin, vincristine, CCNU
- Autologous stem cell rescue
- Children > 3 years
- Craniospinal irradiation
- 23.4 Gy
- Commenced within 40 days of surgery
- Posterior fossa boost to a total dose of 55 Gy
- Children < 3 years
- Repeated cycles of chemotherapy have been used after surgery in those < 3 years in an attempt to prevent progression until they become eligible for radiotherapy.
- Outcome (Gajjar 2006)
- 5 year OS 85%
- 5-year event-free survival 83%. For the ones who got radiotherapy
High risk
- Criteria
- Age <3
- Chang stage M1-M4
- CSF positive for tumour cells (LP>15 days post op)
- Residual tumour > 1.5 cm² despite 2nd Look Surgery
- Histology risk (WHO 2007)
- Large Cell Medulloblastoma
- Anaplastic Medulloblastoma
- Molecular risk
- TP53 mutation in SHH subgroup
- MYC or MYCN amplification
- Treatment
- All children
- Surgery then Induction chemo
- Carboplatin
- Etoposide
- Stem cell rescue
- Then one the following experimental trial
- High-dose chemotherapy (Thiotepa) prior to (or occasionally post-) + craniospinal RT
- Craniospinal irradiation
- 36 Gy
- Commenced within 40 days of surgery
- Posterior fossa boost to a total dose of 55 Gy
- Hyperfractionated accelerated radiotherapy (HART)
- 39 Gy to the neuraxis
- 2 fractions per day
- Also tumour bed boost (increased dose-intensity of radiotherapy)
- Conventional craniospinal RT (once daily)
- Most commonly used prior to maintenance chemotherapy
- Conventionally fractionated irradiation at 36 Gy to the neuraxis plus tumour bed boost delivered after high-dose chemotherapy and stem cell rescue (increased dose-intensity of chemotherapy)
- Outcome (Gajjar 2006)
- 5 year OS: 70%
- 5-year event-free survival 70%
- Packer 1991:
- The addition of chemotherapy to medulloblastoma treatment adds a survival benefit over radiation and surgery alone, particularly in high risk patients
- 88% chemo radiation versus 44% radiation alone
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