RADIOTHERAPY PROTOCOL: Intracranial Stereotactic ...

OXFORD CANCER CENTRE

Authorised By: CLINICIAN: K. Shah

PHYSICS: S. Padmanaban

PRE-TREATMENT: S. Duxbury

TREATMENT: E. Lewis

Filename: CD-L3-018

Page 1 of 28 Issue Date: 1.3.2021

Issued By: V. Stopforth

Version: 9

DO NOT PHOTOCOPY

RADIOTHERAPY PROTOCOL: Intracranial Stereotactic Radiosurgery, Stereotactic Radiotherapy

and Fractionated Stereotactic Radiotherapy

Updated February 2021 by the OUH CNS SRS/SRT group Clinicians: Dr C Hobbs (SRS/SRT Lead) and Dr M. Nandhabalan Radiographers: Ms R Watson, Ms E. Lewis, Mrs D. Duxbury, Mr W Fenwick, Physicists: Dr S Padmanaban, Ms C. Tunstall Pharmacist: Ms S. Castro Acknowledgment is made to the ExacTrac SRS teams in Edinburgh, The Royal Marsden Hospital and Manchester for sharing their SRS protocols and expertise. Definitions of Acronyms and Abbreviations used within this document are found in CD-L4-001.

NB: See local COVID-19 guidance including priority categorisation and fractionation

Index 1. Primary Objective & Scope .................................................................................................................... 2

2. Definition of intracranial SRS / SRT/ fSRT ............................................................................................. 2

3. Indications for SRS/SRT/fSRT in OUH ................................................................................................... 2

4. Pre-Radiotherapy Investigations ............................................................................................................ 7

5. Volume Definition ................................................................................................................................. 8

6. Therapeutic Schema ............................................................................................................................12

7. Dose Calculation and plan evaluation ..................................................................................................14

8. Quality Assurance and Approval Criteria ...............................................................................................18

9. Review on treatment, treatment delays and side effects ........................................................................18

10. Follow-up after SRS treatment ............................................................................................................20

Appendix 1: Audit .....................................................................................................................................21

Appendix 2: House Brackmann Scale .......................................................................................................22

Appendix 3: Diagnostic imaging requirements for pre-treatment imaging...................................................24

Appendix 4: Follow up requirements for skull base fSRT (excluding pituitary) ............................................25

Appendix 5: SRS/SRT patients ONLY Guidance for action to be taken during breakdown on Varian 5 or ExacTrac ..................................................................................................................................................26

Appendix 6: fSRT patients ONLY: Guidance for Action to be taken when Varian 5 is unavailable or during breakdown of ExacTrac - see also wording on page 23.............................................................................27

Appendix 7: References ...........................................................................................................................28


Filename: CD-L3-018 SRS/ SRT/ fSRT

Page: 2 of 28 Issued By: V. Stopforth

Version: 9

DO NOT PHOTOCOPY

1. Primary Objective & Scope

To summarise the planning and treatment of patients receiving stereotactic radiotherapy for intracranial indications at the OUH.

Responsibilities for the process are described within CD-L2-001.

The departmental Patient Identification policy (OCC-RT-L3-019) must be adhered to throughout the process.

2. Definition of intracranial SRS / SRT/ fSRT

SRS/SRT is a highly conformal radiotherapy treatment to a precisely delineated target volume, delivered using stereotactic localisation techniques. A multidisciplinary team of neurosurgeons, neuro-oncologists and neuro-radiologists be involved in case selection, treatment planning and delivery. Target delineation will be performed by a neuro-oncologist with input from a neuroradiologist +/- sub-specialised neurosurgeon.

A. SRS - stereotactic radiosurgery delivered in a single fraction of RT

B. SRT - stereotactic radiotherapy delivered in 2-5 fractions

C. fSRT - stereotactic radiotherapy delivered in conventional fractions (25-33)

The service specification for SRS/SRT is NHSE Clinical Commissioning Policies NHSE D05/S/a 2013 and fSRT is covered in the radiotherapy specification (NHSE B01/S/a 2013).

Treatment in OUH is delivered on a Varian Clinac (Varian 5) with 120 MLC using the ExacTrac immobilisation and patient imaging and verification system (kV and infrared) before and during treatment, using the 6 degree of freedom robotic couch to correct for position.

Stereotactic masks are used to deliver SRS, SRT and some indications for fSRT (Vestibular Schwannoma, skull base glomus tumours and paragangliomata, meningioma, and pituitary adenomas).

Conventional thermoplastic masks are used for some fractionated fSRT indications in extenuating circumstances.

Treatment may be delivered with multiple fixed conformal or IMRT fields, or dynamic conformal arc (DCA), or RapidArc as defined by the optimal treatment plan.

3. Indications for SRS/SRT/fSRT in OUH

In line with the NHSE Clinical Commissioning Policies for SRS and SRT (2013)

1. Vestibular Schwannoma (Acoustic Neuroma) or other cranial nerves (e.g. Trigeminal neuroma) (NHSCB/D05/P/a)

2. Skull base glomus tumours and paragangliomata (NHSCB/D05/Pf)

3. Meningioma (NHSCB/D05/P/e)

4. Pituitary Adenoma (NHSCB/D05/PS/ a) – (Craniopharyngioma receives fSRT)

5. Cerebral Metastases (NHSCB/D05/P/d)

MDT Agreement A summary of the MDTs roles is outlined in CD-L2-001.

All cases offered SRS, SRT and fSRT must have been discussed and agreed at the OUH Neurosciences MDT, OUH Pituitary MDT or OUH Skull base MDT. In addition, patients with cerebral metastases must have been discussed and referral agreed at the local tumour site MDT.




Version: 9

DO NOT PHOTOCOPY

Patients with brain metastases who are for SRS should then be assessed by the Neuro-oncologist and Neuro Advanced Practitioner Radiographer or Nurse within 7 days of discussion at the neurosciences MDT, given written information and a written management plan. Written consent must be formally documented. The management plan should be sent to the referring consultant and GP within 2 days. Patients with brain metastases should receive their treatment within 14 days of the decision to treat being made in clinic with the patient.

Exclusion Criteria:

1. Patient inability to provide informed consent or comply with the treatment

requirements

2. Patient inability to undergo MRI imaging is a relative contraindication, depending on the quality of CT scans available.

Inclusion Criteria:

A. Vestibular Schwannoma (VS) (Acoustic Neuroma) other cranial nerve neuromas

Indications:

• Newly diagnosed as an alternative to surgery

• Residual disease after microsurgery

• Recurrent disease after surgery

• Intracanalicular tumours if tumour growth is documented after observation.

• NF2 patients requiring SRS will be referred to the national treatment centre for NF2 in Sheffield.

NB Histological verification is not required.

Technique:

• SRS may be used where the tumour is less than 3 cm in extra-canalicular diameter AND there are no clinical signs of brainstem compression AND the length of the VIII nerve in the PTV is <0.2cm. If the shape of the tumour is a narrow cylinder, the maximum tumour dimension may be up to 5cm.

• fSRT with conventional 1.8Gy fractionation over 5-6 weeks can be used for tumours larger than 3 cm diameter OR with clinical signs of brainstem compression where surgery is not an option OR following surgery for residual large volume disease.

Outcome:

• Compared with surgery, SRS gives similar levels of tumour control (95% at 5 years and 93% at 10 years), with better levels of facial nerve (95%) and hearing preservation (70% at 10 years), a less detrimental impact on quality of life and lower rates of procedural mortality and medium-term treatment related complications.

• Risk of neuropathy following fSRT is 1-3% and disease control 93% at 5 years and 86% at 15 years.

• Patients aged ≤ 60 years and those with tumours ≤1.5cm3 may have better facial nerve preservation with SRS than those over 60 and with larger lesions.

• Note that 30% may show transient increase between 6 and 30 months post SRS before shrinking. Up to 10% may develop hydrocephalus.

• 3% of patients treated will require subsequent surgical resection.

• Note that in some SRT series (e.g. 25Gy in 5 fractions) disease control is 82% and hearing preservation 30% so this option will not be used in the OUH.




Version: 9

DO NOT PHOTOCOPY

B. Skull base glomus tumours and paragangliomata.

Indication and technique:

• SRS may be used where the tumour is less than 3 cm diameter where surgery is contraindicated or relative risks of surgery are high, or for recurrence <3cm following surgery.

• fSRT in 1.8Gy fractions should be used for unresectable or residual tumours >3cm diameter.

• NB Histological verification is not required where radiology is certain.

C. Meningioma

Indication

Grade 1 and 2:

• Symptomatic/critical sites, where resection is not possible. NB Histological verification is not required if radiology is certain.

• Following sub-total surgical resection in symptomatic/critical sites (treat all grade 2 with residual post op)

• Recurrence following surgery (including residual after second operation).

• Consider ROAM trial for patients with grade 2 meningioma.

Grade 3:

• Any patient with grade 3 meningioma following resection or not.

Technique:

• SRS may be used for benign (grade 1 and 2) lesions <20cm3 and >0.3cm to optic nerve/chiasm,

• SRS may be used for meningiomas <13cm3 adjacent to brainstem or located on the convexity of the skull.

• SRS may be used for small recurrence following fractionated RT and fSRT may be used to treat large volume recurrence following SRS.

• fSRT should be used for:

o All lesions <0.3cm to optic chiasm / nerve,

o Any meningioma >3 cm diam.

• Conformal RT or IMRT/RapidArc in fractions using conventional immobilisation may be used for larger meningioma which are not adjacent to critical structures.

Outcome:

• Grade 1 and 2 meningioma: >90% tumour control at 5 and 10 years following SRS and fSRT approx. 30% reduction in size (not usually significant reduction)

• Grade 3 meningioma: 80% PFS at 5 years, compared with 15% for surgery

D. Pituitary Adenoma

Indication:

• Documented progression following initial surgery, especially if threat to function

• An enlarging tumour which may require further surgery in the future and treatment would be aimed at avoiding it.

• secreting adenomas are refractory to maximal biochemical control

• Significant extra-sellar inoperable residual disease (e.g. cavernous sinus) following initial surgery.




Version: 9

DO NOT PHOTOCOPY

Technique:

• fSRT – indications a - c above as first line therapy.

• SRS – may be used for primary disease or for small volume symptomatic (including secreting) pituitary recurrence following surgery and or conventional RT /fSRT and the recurrence is >0.3cm from the optic chiasm and tumour volume <4cm3.

Outcome:

• 10 year control rate is in the region of 90 – 95% for SRS and fSRT

• Biochemical disease control 44% at 6 years for SRS (GH secreting) and 50% for fSRT

• Fractionated radiotherapy to pituitary adenomas is associated with

o 1-2% risk of radiation optic neuropathy

o 20-30% risk of developing pituitary hormone deficiency requiring replacement therapy

o 4 fold increase in relative risk of CVA.

E. Craniopharyngioma.

Indication:

• Following subtotal resection

• Cystic enlargment despite initial resection.

Technique:

• fSRT

• CBCT to monitor cystic changes weekly during treatment. May need replan if cyst enlarges beyond CTV

Outcome:

• Subtotal surgery and radiotherapy reduces recurrence rate from 73% recurrence with surgery alone, to 17%

• Improved 10 year survival (77% RT + surgery vs 37% surgery alone)

F. CNS Metastases

Indication:

i. Initial treatment of metastases:

The role of single fraction SRS in the primary treatment of CNS metastases is considered particularly useful for patients whose brain metastases are of small volume and surgically inaccessible, or with high risk of new deficit after surgery.

• Patients must have a Karnofsky Performance Status (KPS) ≥ 70 (WHO PS ≤ 2)

• The diagnosis of cancer must be established and there must be absent or controllable primary / metastatic disease.

• The tumour site MDT has confirmed that the patient’s life expectancy from any treatable extra-cranial primary or metastatic disease is expected to be greater than 6 months

• Pressure symptoms which would be best relieved by surgery are excluded.

• Pre-treatment scans must not show a total tumour volume of more than 20cm3. This will usually mean that no individual tumour has a diameter in excess of 3cm. Multiple lesions totalling up to 20cm3 may be treated but not likely to be more than 3 lesions.

• Patients should be treated within 2 weeks of decision to treat in clinic




Version: 9

DO NOT PHOTOCOPY

ii. Recurrent treatment of metastases with SRS/SRT:

• SRS/SRT may be used to treat new lesions in patients where SRS/SRT has previously been effective, provided: 1. A period of three months has elapsed since the last SRS/SRT treatment 2. AND the above criteria (for initial treatment of metastases) are all met 3. AND the disease specific cancer MDT has reviewed the patient and confirmed

the appropriateness of further SRS/SRT

• Repeat treatment of lesions previously treated with SRS/SRT or WBRT will only be supported if: 1. A period of six months has elapsed since the last SRS/SRT/WBRT treatment 2. AND criteria above (for initial treatment of metastases) are all met 3. AND the disease specific cancer MDT has reviewed the patient and confirmed

the appropriateness of further SRS/SRT

• SRS may be used to treat the tumour bed for incompletely resected metastases as shown on immediate post op MRI or for resected metastases following an MRI >4 weeks post-surgery if the above criteria for SRS are met.

Technique:

• SRS may be used for lesions total volume <20cm3 (~3cm maximum diameter; see section 7 for diameter/volume guide) which are not in critical locations: i.e. brainstem, basal ganglia or internal capsule.

• SRT (3-5 fractions) is used for metastases total volume <20cm3 in critical locations such as in brainstem, adjacent to optic structures, basal ganglia or internal capsule OR if normal brain dose constraints are not met for single fraction technique.

• Whole brain radiotherapy (WBRT) following surgery or radiosurgery does not confer a survival benefit (median survival is 10 months with surgery or SRS +/- WBRT), but does delay neurological progression by 1.2 months. A dose of 30Gy in 10 x 3Gy fractions WBRT will be used if there is evidence of intracranial disease progression only. However, note that WBRT within 6 months before or after SRS increases the risk of OAR toxicity especially to brainstem. EORTC trial (Kocher et al JCO 2011)

Treatment 2 year local site relapse 2 year other CNS relapse

Surgery 59% 42%

Surgery + WBRT 27% 23%

SRS 31% 48%

SRS + WBRT 19% 33%

For patients treated with SRS following surgical resection, local relapse at 12 months is 28% vs 58% with surgery alone, however overall survival is unchanged.

Recovery of neural tissue after a first radiation course is only initiated by 6 months, with progressive increments at subsequent years up to three years. Some guidance may be obtained from figure 1, which represents a cautious interpretation of experimental data sets. Each hashed curve from the bottom curve upwards represent 6 months, 1 year, 2 year and 3 years respectively. BED calculations must also be done to provide the actual doses that can be given.




Version: 9

DO NOT PHOTOCOPY

Figure 1 Plot of first and second course percentage tolerance BED, for increasing intervals of time between courses, for lowermost 6 months, followed by 1, 2 and 3 years in an upward direction. Outcome: Overall Median Survival following SRS is 10 months. For patients with RTOG RPA class 1 (KPS >=70, <65 years, controlled primary, no extra-cranial metastases) the median survival following SRS is 18 months. For all other patients median survival is 8 months following SRS. 4. Pre-Radiotherapy Investigations

As per departmental guidelines, to be completed prior to radiotherapy procedures.

For brain metastases patients – CT CAP within 4 weeks of SRS decision to treat.

Baseline audiology tests are required for Vestibular Schwannoma patients.

Baseline visual field testing and pituitary hormone levels are required for Pituitary Adenoma patients.

Diagnostic imaging: MRI scan whole head should be fused to the planning CT. MRI should be within 2 weeks for cerebral metastases, and 8 weeks for other indications.

See Appendix 3 for further guidance.




Version: 9

DO NOT PHOTOCOPY

5. Volume Definition Image Import and registration

If there are multiple image data-sets required for treatment planning, import images as follows:

1. Primary data set CT Simulation with IV contrast if requested

2. Diagnostic MRI imaging for target delineation (named first by modality then by date e.g., MRgad_Jun09).

MRI -CT fusion:

Diagnostic MRI images will be registered to the planning CT scan. The treating consultant shall review and approve the co-registration.

The Region of Interest window should be limited to the skull to ensure accurate fusion. Use the High Resolution Structure Volume tool for all structures (excluding Body, brain and any support structures) in Eclipse. Radiographer Contouring of Normal Structures

Patients with the stereotactic frameless system:

Couch Structures: ‘BrainLAB/iBeam Couch H&N Extension’ structure must be inserted

as per OCC-PP-L3-120. Couch structure must cover the wooden stereotactic board (used for pre-treatment purposes only) and abut the posterior surface of the carbon fibre stereotactic base frame (shown below in Figure 2).

BL SRS Baseframe: Outline to include levers and clips and superior and inferior

extremities of the base. Body: Automatic ear and nose contours need to be corrected (include thick part of nose bridge). ExacTrac CT markers may be included in auto contour, these must be removed. Copy and paste into ‘Body-Baseframe’ then carry out a Boolean operation to include ‘BL SRS Baseframe’ in the ‘Body’ contour.

Bones: Use segmentation wizard to contour skull bones. No need for any post-processing. ExacTrac CT markers may be included in auto contour, these must be removed.

Brain: Use segmentation wizard to contour brain and correct contours as necessary. After segmentation, convert brain structure to high resolution structure and carry out a Boolean subtraction of the Brainstem. Eyes, lenses, optic nerves, cochlea, spinal cord and brainstem must be contoured by appropriately entitled Radiographers (see OCC-L4-001). Patients with thermoplastic mask set:

Couch Structures: No couch structure should be inserted for cranial patients on the S-frame. ‘BL SRS Baseframe’ should be renamed as ‘Board’ and the S-frame should be contoured under this label.

Body: Automatic ear and nose contours need to be corrected. ExacTrac CT markers may be included in auto contour, these must be removed. Copy and paste into ‘Body-Baseframe’ then carry out a Boolean operation to include ‘Board’ in the ‘Body’ contour.

Bones and brain - contoured as above.

Eyes, lenses, optic nerves, cochlea, spinal cord and brainstem must be contoured by appropriately entitled Radiographers (see OCC-L4-001).




Version: 9

DO NOT PHOTOCOPY

Figure 2. Transverse CT slice of a patient with stereotactic frameless system –note the position of the couch structure (abutting the carbon fibre SRS mask base). Volume Definitions The following target volumes and OARs will be segmented by the consultant oncologist and reviewed by a neuroradiologist. Additional review by a second oncologist is strongly recommended and these may also be reviewed by a neurosurgeon. In the structure set, the consultant oncologist will delineate GTV under ‘GTV_Onc1’ and/or ‘GTV_Onc2, and will add their initials to the structure, and at review with the neuro-radiologist will delineate, ‘GTVRad’. The final reviewed volume must be copied onto the ‘GTV’ structure. To create duplicate structures for multiple GTVs, use the ‘duplicate structure’ tool. For multiple GTVs, label from the most superior to the most inferior, and if lesions overlap axially label from left to right.

GTV CTV (includes MRI fusion/contouring uncertainty)

PTV

Vestibular Schwannoma

Enhancing lesion on MRI or CT if MRI contraindicated – see detailed guidelines below

GTV CTV+0.1cm

Glomus skull base tumour

Enhancing lesion on MRI or CT if MRI contraindicated

GTV CTV+0.1cm (CTV+0.3*- 0.5cm in thermoplastic mask)

Meningioma (SRS) Enhancing lesion on MRI or CT (if MRI contraindicated) + nodular dural tail + hyperostotic invaded bone

GTV CTV +0.1cm (CTV+0.3*- 0.5cm in thermoplastic mask)




Version: 9

DO NOT PHOTOCOPY

GTV CTV (includes MRI fusion/contouring uncertainty)

PTV

Meningioma (fSRT)

Post op Enhancing lesion and resection cavity on MRI or CT (if MRI contraindicated) + nodular dural tail + hyperostotic invaded bone

Grade 1 : GTV + 0.1- 0.2cm Grade 2 or 3: GTV+ 0.5cm in all directions or anatomical boundary, and 1cm along dura and into any involved brain.

CTV+0.1cm (CTV+0.3*- 0.5cm in thermoplastic mask)

Pituitary Adenoma (SRS)

Microadenoma /recurrence as identified on MRI

GTV CTV + 0.1cm

Pituitary Adenoma (fSRT)

All post op residual tumour on MRI (consider including whole of sella, top of sphenoid sinus, whole cavernous sinus if these structures are involved by tumour)

GTV + 0.1-0.2cm


Craniopharyngioma Residual disease on MRI – consider pre op extent. Caution about defining GTV which can vary with dimensions of cyst/efficiency of drain et

GTV + allowance for potential cyst enlargement.


CNS metastases Enhancing lesion or resection cavity on MRI or CT if MRI contraindicated

Tumour: GTV Following resection: GTV to encompass any enhancement and whole resection cavity.

GTV+0.1cm (CTV+0.3*- 0.5cm in thermoplastic mask)

* CTV+0.3cm when using ExacTrac imaging with body markers; CTV+0.5cm for all other imaging modalities




Version: 9

DO NOT PHOTOCOPY

Specific guidelines for Vestibular Schwannoma delineation (from the Christie protocol)

The GTV is the gross (visible) tumour. Usually this will be clearer on MRI than on CT, although the CT is the primary dataset for patient positioning. However, the T1+gadolinium MRI sequence may suffer from geometric distortion and overestimation of the target volume. The GTV outline should therefore also be evaluated with respect to the thin slice FIESTA sequence, which is less prone to these effects. The GTV will usually be drawn to cover the T1+gad extent, but where the tumour is close to or abutting brainstem, covering only the FIESTA extent may be preferable in order to limit brainstem dose. The GTV should also be reviewed on the CT with bone windows, as the intracanalicular part should fit the bony anatomy of the IAC. This is especially critical when it is desired to preserve useful hearing, because the IAC is very close to the cochlea. Overestimation of the intracanalicular part will increase the cochlear dose. In addition, the facial and cochlear nerve usually run along the anterior border of the tumour in the IAC, so that making the volume too large anteriorly may move the nerves into the higher dose region, making them more susceptible to damage. However, this is likely to be much less critical than with Gamma Knife, which has much steeper dose gradients within the PTV.

Figure 3. Axial CT through skull base. IAC, internal auditory canal, EAC, external auditory canal, C, cochlea, V, vestibule (Bhandare et al., 2010)

Figure 4. FIESTA sequence, 0.4 mm slices. The left trigeminal nerve is seen exiting the brainstem (a) and entering Meckel’s cave (b). The right trigeminal nerve is also seen (c). (SRFT imaging).

a

b

c




Version: 9

DO NOT PHOTOCOPY

Organs at risk

The following organs at risk and PRV may be segmented by the Radiographer/dosimetrist /physicist/consultant as appropriate for site of tumour and beam orientation. The treating consultant will have final approval of all structures. Guidance should be sought from Normal Tissue Contouring for CNS Tumours (RTProt/CNS Contouring)

• Optic chiasm • Optic nerves • Orbits

• Trigeminal nerve • Facial nerve • Lenses

• Brainstem • Pituitary • Cochlea

• Normal brain • Hippocampus • Lacrimal gland

• Parotid • Spinal cord • Skin (0.5cm inner margin of patient surface)

Planning risk volumes for Organ at Risk For patients with a stereotactic mask: PRV = OAR + 0.1cm margin For patients with thermoplastic mask: PRV = OAR + 0.2cm margin No margins added for lens, cochlea, pituitary, normal brain outside GTV or CTV. 6. Therapeutic Schema

Prescription

Note that dose should be prescribed according to Volume, a rough guide for a sphere:

volume= 4/3 r3, where r is the radius, or 1/6 d3, where d is diameter, assuming all lesions spherical.

Diameter Volume

1.8 cm 2.9 cm3

+

2.3 cm 7cm3

2.9 cm 13 cm3

3.5 cm 20 cm3

The prescription dose will usually be prescribed to the 60-80% isodose for single fractions and 70-90% isodose for 2-5 fractions and 100% for conventional fractionation respectively. Alternatively, for SRS/SRT this can be done by prescribing to 100% and normalising 100% of dose to typically 95-100% of the volume.

This difference is because hypo-fractionated treatments rather than single fractions are given for lesions adjacent to critical structures and a more homogeneous dose distribution is achieved with a lower maximum leading to less necrosis by prescribing to the 90%. A maximum dose within the PTV will be recorded, which should aim to be <160% of the prescription dose for SRS and <140% for SRT.

Protocol doses (2014) for 3 centres Manchester (M) Edinburgh (E) and Royal Marsden Hospital (RMH) are given for reference.




Version: 9

DO NOT PHOTOCOPY

Site: Tumour Size or

GTV constraint SRS (PTV covered by 60 - 80%)

SRT (PTV 70 - 90%)

fSRT (Prescribed to 100%, PTV 95%)


<3 cm diam (or up to 5cm if cylindrical in shape) AND No brainstem compression. AND <0.2cm Facial nerve in GTV

12 Gy to PTV. (for reference: E=13 1mm PTV margin, RMH=12.5 no PTV margin M=12, 1mm PTV)

No No


Brainstem compression or lesion >3cm

No No 54 Gy in 30 fractions


<3 cm (or up to 5cm if cylindrical in shape) AND No brainstem compression

15Gy as per RCR benign tumour 2015 guidelines

No NO


>3cm OR brainstem compression

No No 45Gy in 25# or 50Gy in 30# depending on size of tumour

Glomus Malignant (consider if SDH mutation positive or higher risk subsite)

Any No No 60Gy in 33#

Meningioma Grade 1 only <13cm3 <0.3cm from optic nerve/chiasm

Any

13-15Gy to PTV No No

Meningioma Grade 1

All others No No 50-54 Gy in 30# (50Gy if close to the globe)

Meningioma Grade 2,3

Any No No 60Gy in 30# or 59.4Gy in 33#

Meningioma Grade 1 Retreatment following fSRT

Skull base <20cm3 Non skull base <13cm3

14 -16 Gy (depending on time since previous treatment + Bleddyn calculator)

Meningioma Grade 1 Retreatment following SRS

14 -16Gy 50-54Gy in 28-30#

Meningioma Grade 2-3 Retreatment following fSRT

Skull base <20cm3 Non skull base <13cm3

14-16Gy 50-59.4Gy in 28-33# depending on critical structures

Meningioma Grade 2-3 Retreatment following SRS

50-54Gy in 28-30#

Pituitary Adenoma Any as per indications

No No 45Gy in 25#. For large lesions or functioning adenomas consider using 50Gy in 30#




Version: 9

DO NOT PHOTOCOPY

Site: Tumour Size or GTV constraint

SRS (PTV covered by 60 - 80%)

SRT (PTV covered by 90%)

fSRT (prescribed to 100%, PTV covered by 95%)

Pituitary Adenoma – >0.3cm from chiasm/optic nerves or recurrence

Recurrence is < 4cm3 AND >0.3cm from the optic chiasm

13-16 Gy to PTV for non-functioning adenomas. Consider up to 20Gy for functioning adenoma NB previous RT lower dose to PTV dep on chiasm dose

No No

Cranio-pharyngioma Post op residual No No 50 Gy in 30# to 55Gy in 35#

CNS metastases/resection cavity NOT in critical location: brainstem, basal ganglia, internal capsule.

GTV <20cm3 18, 21, or 24 Gy to PTV * see below. Give highest dose to achieve Brain V12<10cm3

21, 24, 27Gy in 3# in 7, 8 or 9Gy per # used if Brain V12 is >10cm3 for a single fraction

No

CNS metastases IN critical locations such as: brainstem, basal ganglia, internal capsule, optic structures

GTV<20 cm3

(NB resection cavity can be up to 25 cm3

providing normal brain dose constraints are met)

No 25-30Gy to PTV in 5 x 5-6 Gy#

No

* Note: care is required if multiple metastatic lesions are situated near to each other. A lower dose may be given if intermediate neural tissue doses exceed 8-10Gy. 7. Dose Calculation and plan evaluation Treatment modality and energy, plan guidelines

− Linear accelerator; 6MV photons must be used.

− For patients immobilised with a stereotactic frameless system, stereotactic couch H&N extension will be used as defined in OCC-PP-L3-120.

− Planning technique: Dynamic conformal arc (DCA) or RapidArc using coplanar/non-coplanar beam geometry.

− The isocenter is ideally defined at circumcentre of PTV. In the case of multiple metastases situated near to each other, the isocenter is defined at an equal distance between the circumcentre of PTVs, or plan separately for each PTV. This will depend on the separation between PTVs.

− Field size must correspond nearly identically to the projection of the PTV along a beam’s eye view with 0-0.2 cm additional margin for SRS/SRT and 0.5cm for fSRT. The only exception will be the use of minimum field dimension of 2x2cm when treating small lesions.

− For fSRT, static fields or arcs should avoid the stereotactic mask base – Cranial array locking mechanism/ bolt (Figure 2).

− SRS/SRT plans will be calculated with 0.1cm grid size. fSRT plans with PTV < 3cm diameter will be calculated with 0.15cm grid size and >3cm diameter with 0.25cm grid size.




Version: 9

DO NOT PHOTOCOPY

− SRS/SRT plans will be prescribed to 100% and normalised as 100% of dose to typically 95-100% of the volume.

− For vertex arc, try to avoid beams exiting through the body or minimise exit dose using optimisation tools eg avoidance structure.

Plan evaluation

− The dose distribution and DVHs must be reviewed in absolute dose and colourwash/ isodose lines with particular attention paid to the prescription isodose for SRS/SRT plans.

− For fSRT plans:

• 95% of prescription dose (PD) should cover PTV but may be compromised to meet PRV/OAR dose constraints. The following DVH parameters should satisfy for PTV: D99% ≥ 90%; D98% ≥ 95% (optional constraint); D95% ≥ 95%; D50% = 100%(±0.5Gy) and D2% ≤ 107%.

− For SRS/SRT plans:

• Prescription isodose should cover PTV, but may be compromised to 95% and preferably 99% of PTV to receive prescription dose in order to meet PRV organ at risk dose constraints. GTV MUST be fully covered by prescription dose.

• PTV Dose max < 160% of the prescription dose for SRS (<140% for SRT)

• Target coverage ratio : PTV VPD (cc) / PTV volume (cc)

• Selectivity index: PTV VPD (cc) / Body VPD (cc)

• Paddick conformity index (PCI) = target coverage selectivity

• Gradient index 1 (GI1) = Body V(50% of PD) (cc) / Body VPD (cc)

• Record Gradient index 2 (GI2) = Body V(50% of PD) (cc) / PTV volume (cc)

Parameter Optimal Mandatory

Target coverage ≥ 0.98 ≥ 0.95

Selectivity index ≥ 0.9 ≥ 0.75

Paddick Conformity index ≥ 0.8 ≥ 0.6

Gradient index1 < 3 < 5




Version: 9

DO NOT PHOTOCOPY

Organs at Risk dose limits

SRS single # SRT: 5 x 5 Gy to PTV Or 3x 9Gy to PTV

fSRT 1.8 Gy per #

Brainstem PRV Dmax (0.03cc)

Dmax < 8Gy if previous WBRT. (1% risk) Dmax < 13.5Gy <5%risk if no WBRT. V12Gy <1 cm3

5# Dmax <23Gy (optimal) <30Gy (mandatory) 3# Dmax <18Gy (optimal) <23.1Gy (mandatory) (UK SABR consortium guidelines) (1-5% risk for SRS alone 5-10% risk if WBRT > 6 months)

Dmax 54Gy (2Gy #) if entire brainstem is irradiated. risk <5% aV54-59 <=10cm3 and Dmax = <59Gy risk <5%

Normal Brain outside GTV/CTV

For each metastasis: V>12Gy <10.0cm3 (necrosis rate 10%) V>12Gy <5cm3 (necrosis rare) Plan sum for multiple mets V>12Gy<30.0cm3 Record V>4Gy and V>1Gy

V20Gy< 30cm3 for 5# V18Gy to < 26 cc (3%) for 3# (ESTRO ACROP 2021) Record V>12Gy and V>4Gy

Record V>12Gy and V>4 Gy

Multiple mets V12Gy1# + V19.6Gy3# + V24.4Gy5# < 30cc

Spinal cord PRV Dmax (0.003cc)

D max<5Gy if WBRT. Risk <1% D max 13Gy if no WBRT planned or given (<1% risk)

5# D max <10Gy if WBRT. Risk 1%

D max<15Gy if >6 months since WBRT

D max 48Gy (<1% risk)

3# D max<8.4Gy if WBRT. Risk 1% D max <12.3Gy if >6 months since WBRT

Optic nerve and Chiasm PRV Dmax (0.003cc)

D max10Gy (<10%) Ideally <8Gy (Risk <3%) Pituitary re-treat <4Gy

5# Dmax <12.5 Gy if WBRT OR Dmax <18 Gy if >6 months since WBRT Dmax 25 Gy (3% risk of neuropathy) ESTRO ACROP 2021)

Dmax <54Gy. (RION negligible). Dmax =54-60Gy (3-7% RION)

3# Dmax <10.3 Gy if WBRT OR Dmax <14.7Gy if >6 months since WBRT Dmax19.5 Gy (<3% risk of neuropathy) ESTRO ACROP 2021)




Version: 9

DO NOT PHOTOCOPY

SRS single # SRT: 5 x 5 Gy to PTV Or 3x 9Gy to PTV

fSRT 1.8 Gy per #

Trigeminal and facial nerve Dmax (0.003cc)

Limit dose if possible (overall 2-8% trigeminal neuropathy rate if <13Gy)

Retina or Eye PRV Dmax (0.003cc)

Avoid eyes (<5-8Gy) 5# Dmax <15 Gy if WBRT Dmax <20 Gy if >6 months since WBRT

Dmax 50Gy

3# Dmax <12.3Gy if WBRT D max <16.2Gy if >6 months since WBRT

Lens NB: include potential for movement of lens within anterior half or orbit Dmax (0.003cc)

Avoid eyes(<2Gy to lens) 5# Avoid if possible. D max 6 Gy

D max 6 Gy <1% risk cataract

3# Avoid if possible. D max 5.2Gy

Cochlea Dmax (0.003cc)

Aim for lowest possible dose (eg 4Gy Dmax) BUT Dmax 14 Gy (<25% risk of hearing loss) ESTRO ACROP 2021)

5# Dmax 27.5 (3%) ESTRO ACROP 2021)

Dmax <45Gy

3# Dmax 20 (<3%) ESTRO ACROP 2021)

Hippocampus Avoid if possible Avoid

Pituitary Dmax (0.003cc)

15Gy =30% risk pit failure ≤ 45Gy (20-40% at 5 years)

Parotid gland - Ipsilateral

Aim for ≤25Gy

Parotid gland - Contralateral

≤20Gy

Lacrimal Gland Dmax (0.003cc)

Dmax <30Gy

Skin

D0.5 cm3 <20Gy (from 3# limit BED calculation with α/β=3) PTV within 0.5cm of body surface ≥3# must be used

D0.5 cm3 <39.5Gy (5#) D0.5 cm3 <33Gy (3#) (UK SABR consortium guidelines)




Version: 9

DO NOT PHOTOCOPY

8. Quality Assurance and Approval Criteria

• Prior to signing off the plan as approved, a thorough review and evaluation shall

be performed ensuring plan meets department policy by all members of the interdisciplinary team.

• All radical brain contouring to have second check by appropriately entitled clinician and annotate in patient notes/task pad.

• Physics to perform a plan check and complete Aria questionnaire

• QA of IMRT or RapidArc plan is carried out following OCC-PDS-L3-044 or OCC-

PDS-L3-049 respectively.

• Data entry and checks are carried out following OCC-RT-L2-012

• ExacTrac Patient Data Preparation will be carried out by entitled treatment Radiographers ahead of patient treatment following OCC-VI-L3-025a/b

Daily Linac QA fSRT: Routine daily linac QA (OCC-PDS-L3-040) SRT/SRS: SRT/SRS Winston-Lutz Quality Control QA will be performed following OCC-PDS-L3-039 9. Review on treatment, treatment delays and side effects

Patients will be assessed by the Radiographer taking responsibility for treatment delivery before treatment. Toxicity should be graded according to CTCAE v4.0 Patients undergoing 1-5 fraction treatment should usually receive corticosteroids.

• Dexamethasone 6mg PO od and Ondansetron 8mg PO od should be prescribed to start on the day of treatment and continued until the day after treatment has been completed, along with a proton pump inhibitor e.g. omeprazole 20mg PO od. This may be followed by a dose reduction as instructed by the consultant clinical oncologist.

• If patients take ondansetron 8mg PO od for a few days and is experiencing alteration of normal bowel habit: Encourage fluid intake of 1 ½ to 2 L daily, increase the intake of dietary fibre. If the patient experiences medication induced constipation then consider an osmotic laxative (e.g. macrogols).

• If the patient is already on steroids, the dose should be increased as outlined above on these days. Steroids may not be required for non-metastatic lesions treated with SRS depending on level of oedema/proximity to brain/ brainstem.

• A prophylactic course of anti-convulsant medication is advised for the following:

• tumours >2cm in diameter in the temporal lobe

• tumours >2cm in diameter near the motor strip (ie. posterior frontal/parietal)

• prior evidence of seizure activity • Leviteracetam 500mg BD should be prescribed to start one week before

SRS begins and continue for 6 weeks in total.

Actions if delays or interruptions in treatment – also see Appendixes 5 and 6

In the event of system failure, (ExacTrac or Varian 5):




Version: 9

DO NOT PHOTOCOPY

• On the SRS/SRT treatment day – if a patient has not commenced treatment, the patient will be delayed until the machine is available or for a maximum of 5 treatment days before referral to another SRS centre should be considered by the clinical team.

• During a single fraction SRS treatment where treatment has commenced, the patient should be taken off the treatment bed and if possible, the Linac repaired. If this is likely to take more than an hour, the remainder of the patient’s treatment should be deferred to the following day, if possible, waiting a minimum of 24 hours between treatments.

• Figure 5 shows isoeffective doses for different a/b ratios. The brain tissue (a/b=2 Gy) recovers most efficiently, but the tumour may be assumed to have a higher value, which results in using a more conservative, lower, subsequent dose. The lowest dose is given when a/b=10 Gy for example. The physician must choose which assumption to make.

• During a SRT treatment, follow the above action and reschedule appointments with a day gap if Linac/ExacTrac is fixed within 24 hours. If not, a gap of up to 5 additional treatment days is acceptable.

• In all cases where a breakdown has occurred during treatment and the Linac cannot be repaired within the hour, the Clinician and SRS Physicist must discuss the effect of the treatment gap on the iso-effective doses. A slightly higher prescription dose than originally planned prior to interruption may be necessary for the remaining arcs/ beams.

• During a fractionated course of treatment (fSRT - benign or malignant) – a gap of up to 5 treatment days is acceptable. For plans with a single non-coplanar couch angle (in addition to a couch angle of 0°), treatment with CBCT matching should be considered for a single fraction.

• Beyond this, resting the patient further or re-planning on a standard Linac should be considered at the discretion of the clinician. Patients with a thermoplastic mask can be treated on an alternative Linac as per section 10.

• For patients recieving fSRT in a stereotactic mask for malignant conditions, advice should be sought from the patient’s clinician where unscheduled treatment gaps of more than 5 days will occur.

• CBCT is not recommended for SRS/ SRT as the setup error in OBI > 0.1cm. Only in extenuating circumstances may CBCT be used for SRT following discussion between the clinican, relevant MPE and lead neuro or IGRT Radiographer.

Figure 5




Version: 9

DO NOT PHOTOCOPY

Side-effects of Stereotactic Radiosurgery

Acute (first 6 weeks) 1) Patients receiving SRS are at risk of acute oedema. This can result in symptoms and

signs of raised intra-cranial pressure (headaches, nausea, and sedation); hence corticosteroids are given to all patients. (See section 11 above).

2) Fatigue – most patients receiving SRS say they feel fatigued for the week after treatment.

3) Seizures – patients with superficial lesions, especially those with a history of seizures, have an increased risk of seizures in the weeks following treatment. If this occurs appropriate adjustments to their anti-convulsants should be made.

Early delayed (6weeks to 6 months) 1) Some patients develop oedema, requiring steroids. Any patient developing a new

neurological deficit should have a contrast enhanced MRI scan to investigate the change. If oedema is demonstrated, they should be commenced on dexamethasone 4-12mg PO od, plus PPI which should be titrated down as the patient’s clinical condition allows.

Late 1) Radio-necrosis, the treatment dose should be adjusted to keep the risk of this to 10%

or less. If this cannot be achieved, the balance of toxicity to benefit should be reviewed. If the patient develops symptomatic radio-necrosis, which cannot be controlled with steroids, then resection of the area should be considered. The risk of requiring an operation is approximately 1 in 100 patients treated with SRS.

2) There is a 1-2% 10 – 20 year risk of radiation induced second neoplasm developing. This risk may be higher in NF2 patients.

Vestibular Schwannoma: Specific SRS side effects 1) Acute nausea, lethargy and headache are sometimes seen, 1 in 6 have transient

dizziness. 2) Facial nerve and trigeminal nerve injury – with SRS there is a risk of approximately 10-

15% of temporary and 5% risk of permanent injury to one or other of the nerves. The risk with fractionated treatment appears to be lower.

3) Hearing – patients who have useful hearing may experience a further decline in their hearing, but this is slower than for an un-treated lesion

4) Obstructive or communicating hydrocephalus- patients with large lesions pressing on the brainstem are at risk of this, if localised oedema occurs. All patients with large lesions should be warned of the risk of requiring a VP shunt. (<5% risk)

5) Brainstem injury – the volume of the brainstem within the high dose volume should be kept to a minimum. All patients should be warned that there is a <5% risk of damage to this structure, which can result in worsening balance or weakness of arm and/or leg.

10. Follow-up after SRS treatment

See Appendix 4 for follow up requirements for skull base fSRT (excluding pituitary).

A. Vestibular Schwannoma, skullbase meningiomas, other cranial nerves and glomus tumours The SRS specialist radiographer will call/Video Call the patient at 4 weeks post SRS and refer the patient back to the skullbase team with an MRI request for 6 months post SRS. The patient will then have a Telemed follow-up 7 months post SRS with the results of their




Version: 9

DO NOT PHOTOCOPY

MRI, if appropriate. Long term follow-up will be under the skull base team at the John Radcliffe.

B. Non-skullbase meningiomas The SRS specialist radiographer will call/Video Call the patient 4 weeks post SRS, request a MRI for 6 months post SRS and refer patient back to the referring neurosurgeon for long term follow-up.

C. Pituitary adenoma The SRS specialist radiographer will call/Video Call the patient 4 weeks post RT then refer back to endocrine team for long term follow up. MRI not usually undertaken for follow-up.

D. CNS metastases SRS specialist radiographer will call/Video Call the patient 4 weeks post treatment then refer back to referring/primary Oncologist for ongoing 3 monthly MRI (or earlier if symptoms change) and review. QoL data should be collected. Appendix 1: Audit Steroid dose will be recorded for all patients at 1 month and 3 month visits, and on-going treatment as appropriate for all tumour types. Vestibular Schwannoma and other cranial nerve schwannoma

1. Tumour size 2. Presence of brainstem compression 3. Planning data 4. Pre and post hearing levels (Gardner Robertson scale) and tinnitus. 5. Treatment complications (facial/trigeminal neuropathy, oedema, radionecrosis). (House Brackmann scale). 6. Hydrocephalus 7. Koos stage (1:confined to IAC;2:<2cm diameter;3:>2cm diameter;4:brainstem compression any size.) 8. Any further treatment given. Post SRS Glomus tumours and paraganglioma

1. Treatment parameters including tumour volume, prescription dose 2. Cranial nerve status including facial nerve function and hearing before the treatment 3. Post-radiosurgery complications (including symptomatic oedema, radio-necrosis, neurological deficits) 4. MRI follow-up annually for a minimum of 5 years 5. Cranial nerve status including facial nerve function and hearing annually 6. Survival 7. Any further treatment given post SRS Meningioma

1. Treatment parameters (including marginal dose) 2. Post-radiosurgery complications (including symptomatic oedema, radio-necrosis, neurological deficits including hearing, facial nerve function)




Version: 9

DO NOT PHOTOCOPY

3. Post treatment volumetric assessment of tumour (Suggested at 6 months, annually for 5 years then every 2 years) 4. Survival 5. Any further treatment given post SRS CNS Metastases

1. Karnofsky Performance Status 2. Estimated total tumour volume (cc) 3. No. of tumours 4. Size of largest tumour 5. Dose 6. Fractionation 7. Post-radiosurgery complications (including symptomatic oedema, radio-necrosis, neurological deficits) 8. Survival 9. Any further treatment given SRS Pituitary Adenoma

1. Treatment parameters including tumour volume, prescription dose 2. Optic nerve status – visual acuity and visual fields pre and post treatment (Endocrine team to arrange) 3. Pituitary Hormone levels pre and post treatment (Endocrine team to arrange) 4. Any further treatment post SRS Appendix 2: House Brackmann Scale

Grade Definition

I Normal symmetrical function in all areas

II Slight weakness noticeable only on close inspection. Complete eye closure with minimal effort. Slight asymmetry of smile with maximal effort. Synkinesis barely noticeable, contracture, or spasm absent

III Obvious weakness, but not disfiguring. May not be able to lift eyebrow. Complete eye closure and strong but asymmetrical mouth movement with maximal effort. Obvious, but not disfiguring synkinesis, mass movement or spasm

IV Obvious disfiguring weakness. Inability to lift brow. Incomplete eye closure and asymmetry of mouth with maximal effort. Severe synkinesis, mass movement, spasm

V Motion barely perceptible. Incomplete eye closure, slight movement corner mouth. Synkinesis, contracture, and spasm usually absent

VI No movement, loss of tone, no synkinesis, contracture, or spasm

Gardner Robertson Scale

Grade I (good-excellent)

pure tone audiogram (dB) : 0-30

speech discrimination (%) : 70-100





Version: 9

DO NOT PHOTOCOPY

Grade II (serviceable)


Grade III (non-serviceable)



Grade IV (poor) pure tone audiogram (dB) : 91-max


Grade V (none) pure tone audiogram (dB) : not testable

speech discrimination (%) : 0

NOTE: Note if PTA and speech do not correlate, use lower class.




Version: 9

DO NOT PHOTOCOPY

Appendix 3: Diagnostic imaging requirements for pre-treatment imaging

REQUEST STANDARD MRI HEAD FOR ALL CASES FOR FUSION WITH PLANNING CT SCAN.

Site MRI sequences to be requested CT (if MRI contraindicated) sequences to be requested

Skull base or orbital Meningioma

High res skull base protocol including high res axial 3 mm T1 fat sat post gad. (If done on 3T magnet, volume T1 post gad sequence should also be included.) Standard MRI head for fusion with planning CT.

Helical acquisition post contrast with bone algorithm reconstructions in 3 planes at 1 mm slice thickness and soft tissue algorithm reconstructions in 3 planes at 3 mm slice thickness

Pituitary Adenoma Pituitary protocol + including high res axial 3 mm T1 fat sat post gad. (If done on 3T magnet, volume T1 post gad sequence should also be included.) Standard MRI head for fusion with planning CT.


Craniopharyngioma Pituitary protocol + including high res axial 3 mm T1 fat sat post gad. (If done on 3T magnet, volume T1 post gad sequence should also be included.) Standard MRI head for fusion with planning CT.


Vestibular Schwannoma Post Gad axial FIESTA (GE scanners) or balanced FFE (Philips scanner) (If done on 3T magnet, volume T1 post gad sequence could also be included.) Standard MRI head for fusion with planning CT.


Skull Base Glomus/paragangliomata

High res skull base protocol including high res axial 3 mm T1 fat sat post gad. (If done on 3T magnet, volume T1 post gad sequence should also be included.) Standard MRI head for fusion with planning CT.


CNS Metastases Volume T1 brain post gad in axial plane (e.g. FMSPGR on 3T GE scanners or STEALTH T1 on 1.5T Philips scanner.)

Helical acquisition post contrast with soft tissue algorithm reconstructions in 3 planes at 3 mm slice thickness




Version: 9

DO NOT PHOTOCOPY

Appendix 4: Follow up requirements for skull base fSRT (excluding pituitary)

Request MRI 3 months post-fSRT

Finish fSRT

Churchill OP FU clinic

Churchill OP FU clinic with scan result

Two-yearly MRI, pituitary function (if appropriate) and skull base clinic FU

Skull Base FU clinic

Request MRI and pituitary function (if appropriate) 1 year post-fSRT then refer to skull base surgeon

Yearly MRI, pituitary function (if appropriate) and skull base clinic FU

1 month post-fSRT

2-4 years post-fSRT

5+ years post-fSRT

1 year post-fSRT

3 months post-fSRT


Authorised By: CLINICIAN: K. Shah

PHYSICS: S. Padmanaban

PRE-TREATMENT: S. Duxbury

TREATMENT: E. Lewis

Filename: CD-L3-018

Page 26 of 28 Issue Date: 1.3.2021

Issued By: V. Stopforth

Version: 9

DO NOT PHOTOCOPY

Appendix 5: SRS/SRT patients ONLY Guidance for action to be taken during breakdown on Varian 5 or ExacTrac – see also wording on page 23

SRS PATIENT

VARIAN 5/EXACTRAC BREAKDOWN

BREAKDOWNPRIOR

TO SRS BEINGADMINISTERED

BREAKDOWNDURING

SRS TREATMENT

RESCHEDULE AS SOON AS

POSSIBLE, MAX DELAY OF 5 TREATMENT

DAYS.

RECORD TIME OF BREAKDOWN . CONSULT CLINICIAN, SRS MPE OR

NEURO RADIOGRAPHER

LINAC FIXED WITHIN AN HOUR OF BREAKDOWN?

YES NO

DELIVERREMAINDER OF

TREATMENT

RESCHEDULE PT THE FOLLOWING DAY IF POSSIBLE, A MINIMUM OF 24 HOURS LATER (MAX DELAY 5 TX DAYS).REMAINING DOSE MUST BE REVIEWED BY THE CLINICIAN & SRS PHYSICIST DUE TO GAP IN TREATMENT.

SRT PATIENT

VARIAN 5/EXACTRAC BREAKDOWN

RECORD TIME OF BREAKDOWN .CONSULT CLINICIAN, SRS MPE OR

NEURO RADIOGRAPHER

RESCHEDULE AS SOON AS

POSSIBLE. MAX DELAY OF 5TREATMENT

DAYS.LINAC FIXED WITHIN AN HOUR OF

BREAKDOWN?

BREAKDOWNPRIOR

TO SRT BEINGADMINISTERED

BREAKDOWNDURING

SRT TREATMENT

YES NO

DELIVER REMAINDER OF

TREATMENT

RESCHEDULE PT THE FOLLOWING DAY IF POSSIBLE, A MINIMUM OF 24 HOURS LATER (MAX DELAY 5 DAYS). REMAINING DOSE MUST BE REVIEWED BY THE CLINICIAN AND SRS PHYSICIST DUE TO GAP IN TREATMENT. CONSIDER SCHEDULE OF REMAINING FRACTIONS.




Version: 9

DO NOT PHOTOCOPY

Appendix 6: fSRT patients ONLY: Guidance for Action to be taken when Varian 5 is unavailable or during breakdown of ExacTrac - see also wording on page 23

EXACTRAC BREAKDOWN

STEREOTACTIC MASK

THERMO-PLASTIC MASK

CBCT ON V5

CBCT ON ANY RA MACHINE

TOLERANCE 0mm & 2°OCC-VI-L3-002kk

FOR ONE FRACTION ONLY

INFORM CLINICIAN/NEURO ONCOLOGY ADVANCED PRCTICIONER

REST FOR UP TO5 DAYS IF

EXACTRAC STILL UNAVAILABLE

GUIDANCE TO BE SOUGHT FROM CLINICIAN/NEURO ONCOLOGY ADVANCED

PRACTICIONER IF EXACTRAC STILL UNAVAILABLE

BENIGN MALIGNANT

VARIAN 5 UNAVAILABLE

STEREOTACTICMASK

THERMOPLASTIC MASK

FOR ONE FRACTIONONLY

CBCT on any RA machine

TOLERANCE 0mm & 2°OCC-VI-L3-002kk

INFORMCLINICIAN/NEURO ONCOLOGY ADVANCED PRCTICIONER

BENIGN MALIGNANT

REST FOR UP TO 5DAYS IF V5 STILL UNAVAILABLE

GUIDANCE TO BE SOUGHT FROM CLINICIAN/NEUROONCOLOGY ADVANCED

PRACTICIONER IF V5 STILL UNAVAILABLE

- Brainlab couch overlay to be set ,,up with inferior index bar only. - Sup end of overlay must be ..flush with sup end of treatment ..couch. - Non-slip mat to be placed ..UNDER brainlab couch overlay. - Sagittal laser line marked on ..sup end of overlay and inferior ..index bar for alignment. ..

(Gantry to be rotated to view ..sagittal laser).- Do not hold the couch overlay ..when moving treatment couch ..in lat/long directions.




Version: 9

DO NOT PHOTOCOPY

Appendix 7: References Fabien Litre et al Fractionated stereotactic radiotherapy for acoustic neuromas: A prospective monocenter study of about 158 cases Radiotherapy and Oncology 106 (2013) 169–174 Stephanie E. Combs et al. Hearing preservation after radiotherapy for vestibular schwannomas is comparable to hearing deterioration in healthy adults and is accompanied by local tumour control and a highly preserved quality of life (QOL) as patients’ self-reported outcome Radiotherapy and Oncology 106 (2013) 175–180 Murphy ES, Suh JH. Radiotherapy for Vestibular Schwannomas: A critical review. International Journal of Radiation Oncology Biology and Physics. 2011;79(4):985-997 Maclean et al. Controversies in Radiotherapy for Meningioma Clinical Oncology 26 (2014) 51-64 Kocher M, Soffietti R, Abacioglu U et al Adjuvant Whole-Brain Radiotherapy versus Observation after Radiosurgery or Surgical Resection of One to Three Cerebral Metastases: Results of the EORTC 22952-26001 Study J Clin Onc, 2011;29:134-141 Minniti G, Clarke E, Lanzetta G et al. Stereotactic radiosurgery for brain metastases: analysis of outcome and risk of brain radionecrosis. Radiation Oncology 2011; 6:48 Ernst-Stecken, Ganslandt O, Lambrecht U et al. Phase II trial of hypofractionated stereotactic radiotherapy for brain metastases: Results and toxicity Radiotherapy and Oncology 81 (2006) 18–24 Choi CY, Chang SD, Gibbs IC et al. Stereotactic radiosurgery of the postoperative resection cavity for brain metastases: prospective evaluation of target margin on tumour control. Int J Radiat Oncol Biol Phys. 2012 Oct 1;84(2):336-42. Breneman JC et al. Frameless image guided SRS: clinical outcomes for brain metastases. IJROBP (2009) Brada M, Radiotherapy for benign tumours coming of age; example of vestibular schwannoma. Radiotherapy and Oncology (2013) 106:157-160 Normal Tissue tolerance doses See QUANTEC papers Int. J. Radiation Oncology Biol. Phys., (2010) Vol. 76, No. 3, Supplements

http://www.ncbi.nlm.nih.gov/pubmed?term=Choi%20CY%5BAuthor%5D&cauthor=true&cauthor_uid=22652105

http://www.ncbi.nlm.nih.gov/pubmed?term=Chang%20SD%5BAuthor%5D&cauthor=true&cauthor_uid=22652105

http://www.ncbi.nlm.nih.gov/pubmed?term=Gibbs%20IC%5BAuthor%5D&cauthor=true&cauthor_uid=22652105

RADIOTHERAPY PROTOCOL: Intracranial Stereotactic ...

Documents