1. The Bristol Gamma Knife Centre & NICE Adult Brain Tumour Guidelines
Dr Alison Cameron
Consultant Clinical Oncologist

2. Stereotactic Radiosurgery / Radiotherapy in Bristol
Service commenced in utilised a modified Linac. Initially treated patients with brain metastases, later extended to benign disease
Gamma Knife (Perfexion) October 2013, upgraded to Icon July 2015.
Market-leading intracranial SRS/SRT machine in terms of conformality and dose drop-off- minimises the dose to normal brain
Icon
Frame- single fraction treatments where high precision needed- for example- pituitary adenomas close to chiasm, or if a patient can not tolerate a mask (claustrophobia)
Mask with intra-fraction monitoring:
Single fraction treatments in patients where a frame is higher risk (post craniotomy)
Multiple fraction treatment

3. Stereotactic Radiotherapy (2-30 fractions)
Government define SRT (for SRT tariff) as 2-5#
5# SRT for large meningioma with significant oedema who are not suitable for operation
25-30# SRT small (<10cc) benign tumours 0-2mm to optics or within brainstem where SRS is higher risk to normal tissue but want to spare normal brain from long term effects of wider fields from VMAT/IMRT
2-3# Adaptive SRT- for large metastases where tumours have time to shrink between the 2 weekly fractions so reducing the normal brain dose and increasing tolerability

4. 12Gy
22.5Gy
8Gy
4 Gy
12Gy
12Gy
8Gy
4Gy
8Gy
FGK 0.5mm PTV
VMAT 1 mm PTV

5. Dosimetric Study: Fractionated Gamma Knife v 7 field RT (v VMAT)
GTV mean 3.2cc [ cc]
Dose to optic apparatus/ orbit: no difference
Homogeneity:
D5 higher with FGK v Linac plans: 116% v 102% (p<0.05)
All FGK plan hot spots within the tumour- at least 1.5mm away from any part of the optic apparatus
FGK
7F 1mm
FGK v 7F 1mm
7F 5mm
FGK v 7F 5mm
Hippocampus median
3.2 Gy
8.5Gy
p=0.003
10.6Gy
p=0.0001
Factor Difference 1
2.7
3.3
>=50% dose
8.1cc
27.4cc
p<0.0001
49.4cc
p=0.0002
3.4
6.1

6. Trigeminal Schwannoma 54Gy in 30# covering PTV by 90%
Protons
Yellow=5Gy
Purple =30Gy
Red=50.4Gy
FractionatedGamma Knife

7. #2: 10Gy 4.512cc 31 mins No additional CBCT #1: 10Gy 6.972cc
2 small metastasis (0.1cc) 24Gy each
total 1 hour 8 mins
No additional CBCT
#2: 10Gy cc
31 mins
No additional CBCT
#3: 10Gy cc
39 mins
2 extra CBCT due to movement >1mm

8. Treatment at The Bristol Gamma Knife Centre:15 Oct 2013-13 Oct 2016
mets (383)
AN (134)
Meningioma (57)
TN (38)
Pituitary (14)
Other (22)
Total=648 pt
Mask= 78 pt

9. Commissioning Process 2015/2016
Tier 1&2- 17 centres around the UK each associated with a neurosurgical centre. Treat adults (>=16yr) brain metastases and benign brain tumours with 1-5#
Tier 3&4- Adult Functional (TN) and all ages Vascular (and non- commissioned tumours agreed through IFR). 2 England Centres (London- south; Sheffield- North)
Paediatric tumour- 2 England Centres (London- south; Leeds- North)
Substantial QA process- testing machine accuracy, contouring and planning. All tomotherapy machines not commissioned after this process, several linac centres required help with planning to achieve adequate plans. Complex cases push limits of linac planning.

10. South West Area
Joint service with Plymouth given geography of region- both centres must treat >100 pt
Meeting December 2016 to agree joint protocols
Recent sad changes in Plymouth- service may require additional support from Bristol
Extensive (but poorly written) outcome data upload required by NHS England

11. NICE Adult Brain Tumour Guidelines
Limited to management of suspected glioma, meningioma and brain metastases, and, for rehabilitation, all patients with brain tumours
Scoping workshop (April 2016)- attended by myself and Marcus Bradley representing Bristol.
Committee- 3 Neurosurgeons, 3 Clinical Oncologist, 3 Patient/Carer, 2 CNS, 2 AHP (OT and Psychologist), 1 Neurologist, 1 Pathologist, 1 Radiologist, Guideline Alliance team- reasearchers, project managers, health economist.
First meeting July Completion Nov 2017.

12. 1.1 What is the most effective diagnostic imaging in newly diagnosed glioma?
1.2 What is the most effective diagnostic imaging in newly diagnosed meningioma?
1.3 What is the most effective diagnostic imaging in newly diagnosed brain metastases?
1.4 What are the most useful molecular markers to guide treatment for gliomas?
1.5 What are the most useful molecular markers to estimate prognosis for gliomas?
2.1 What is the optimal initial treatment (surgery [including extent of resection], radiotherapy, observation, chemotherapy or combinations of these) for low grade glioma?
2.2 What is the most effective method of resecting high-grade glioma (for example with 5ALA, awake craniotomy, intraoperative ultrasound, intraoperative MRI)?
2.3 What is the optimal management (surgery, radiotherapy, chemotherapy, combinations of these, or other therapies such as metformin or tumour-treating fields) of recurrent high-grade glioma?
3.1 Which adults with previously untreated meningioma should have radiotherapy?
3.2 Which adults with recurrent meningioma should have radiotherapy?
4.1 What is the most effective intracranial treatment (surgery, stereotactic radiotherapy, whole-brain radiotherapy or combinations of these) for a single brain metastasis?
4.2 What is the most effective intracranial treatment (surgery, stereotactic radiotherapy, whole-brain radiotherapy, combinations of these, or no treatment) for multiple brain metastases?
5.1 What is the most effective follow-up protocol (including duration, frequency and tests) to detect recurrence after treatment for glioma?
5.2 What is the most effective follow-up protocol (including duration, frequency and tests) to detect recurrence after treatment for meningioma?
5.3 What is the most effective follow-up protocol (including duration, frequency and tests) to detect intracranial recurrence after treatment for brain metastases?
5.4 What is the most effective surveillance protocol (including no surveillance) for detecting late effects of treatment for glioma, meningioma or brain metastases?
5.5 What are the health and social care support needs of people with brain tumours (primary) and brain metastases and their families and carers?
6.1 Which adults with primary brain tumours or brain metastases should be referred for neurological rehabilitation assessment and when is the optimal time to refer?