Stereotactic RadiosurgeryStereotactic Radiosurgery

Gamma knifeGamma knife

CyberknifeCyberknife

Trends in Melanoma Incidence and Mortality in the

United States

Brain Metastases• 20%–40% of all patients with cancer

develop brain metastases

• Retrospective analysis indicates primary malignancy as:

– Lung cancer (40%)

– Breast carcinoma (17%)

– Malignant melanoma (11%)

• Increasing incidence due to:– Improved treatment of primary malignancy

– Earlier detection of brain metastases

Nussbaum ES et al. Cancer. 2000;78:1781-1788.

Primary and secundary CNS Tumors: Incidence

November 2002

Type of Intracerebral Tumor * Percent Incidence

Secondary carcinoma 40

Gliomas, all types 40

Meningiomas 13

Pituitary adenomas

Neurofibromas

Congenital tumors

Tumors of blood vessels

Others tumors

4

3

* These figures apply to adult populations. In children, about three-quarters of cerebral tumors are gliomas.

Secondary Brain Tumors: Incidence by tumor type

November 2002

Primary Tumor Patients Percentage

Lung

Breast

Melanoma

Colon

Other known primary

Unknown primary

Total

270

82

50

26

72

61

561

48

15

9

5

13

11

100

RESULTS

Changes in Overall CancerMortality (1975-2003), United States

-60

-40

-20

0

20

40

Per

cent

age Melanoma

Prostate Cancer

Breast Cancer

Colorectal Cancer

Cervical Cancer

US SEER Cancer Registry, 2003

Metastatic Brain Tumor• History

– Rapidly progressive onset of symptoms (weeks vs. months) – Most common sources are LUNG, BREAST (in women), RENAL, & G.I. tract

• Diagnostic Imaging Studies– MRI: Tumor at grey-white matter

junction, usually associated with edema– Systemic work-up includes CT scan of

chest and abdomen• Diagnostic Laboratory Studies

– Liver function tests, CBC w/diff• Treatment

– For solitary lesion or less than 4 lesions all < 3 cm. – biopsy if undiagnosed, plus Gamma Knife

– For > 3 cm. tumor, surgery followed by WBRT

– For > 4 lesions, biopsy for diagnosis, plus whole brain radiation therapy.

• Prognosis: 7 – 12 mos.

http://www.neurobc.com/conditions/Brain_metastases.htm

MetastasesMetastases Outnumber all other brain tumors combinedOutnumber all other brain tumors combined >100,000 patients die each year with >100,000 patients die each year with

symptomatic brain metssymptomatic brain mets Common primary tumors:Common primary tumors:

– LungLung– BreastBreast– RenalRenal– MelanomaMelanoma

MetastasesMetastases Medical therapy - steroidsMedical therapy - steroids

– Often dramatic relief of symptomsOften dramatic relief of symptoms Surgical excisionSurgical excision Conventional radiotherapyConventional radiotherapy RadiosurgeryRadiosurgery

Brain metastasesBrain metastases

Tsao et al, Cancer Tr. Rev. 2005Tsao et al, Cancer Tr. Rev. 2005– EBRTEBRT– Stereotactic RTStereotactic RT

60-90% improvement of60-90% improvement of

neurological symptomsneurological symptoms OS benefit in single metastasisOS benefit in single metastasis

Secondary Brain Tumors: Radiotherapy

November 2002

RadiosurgeryRadiosurgery

One time application of high dose, focused One time application of high dose, focused radiationradiation

A variety of machines used to produce the A variety of machines used to produce the radiationradiation– Gamma knifeGamma knife– LINACLINAC– Particle acceleratorParticle accelerator

Stereotactic MRI - Image Fusion

• Volumetric MRI sequence

• Rapid, thin slices, no special equipment

• Avoids errors inherent to direct stereotacticacquisition of MRI data

• Introduces error of image fusion (pixel size)

Dose Planning

• Major goal: Conformality– Maximum dose to target

– Minimum dose to surrounding tissue

• Tools– Arc weighting

– Arc span adjustment

– Multiple isocenters

Whole brain radiation therapy vs. Stereotactic radiosurgery

Role of Stereotactic Radiosurgery in the Management of Brain Metastases

In patients with one brain metastasis without evidence of active cancer elsewhere As a radiation boost following surgical

removal of the metastasis and/or whole brain radiation therapy

In patients with one to three recurrent brain metastases following previous whole brain radiation therapy

What is Stereotactic What is Stereotactic Radiosurgery?Radiosurgery?

It is a procedure that has to do with It is a procedure that has to do with delivering high doses of radiation to delivering high doses of radiation to specific targets in the body in order to specific targets in the body in order to destroy tumors, lesions and other destroy tumors, lesions and other cancerous tissue. It uses cross-fired cancerous tissue. It uses cross-fired beams of radiation delivered from multiple beams of radiation delivered from multiple points outside the body. Radiosurgery has points outside the body. Radiosurgery has been around since the early Sixties.been around since the early Sixties.

Computerized Image of Computerized Image of RadiosurgeryRadiosurgery

What is Gamma Knife?What is Gamma Knife?

Side view of the Gamma KnifeSide view of the Gamma Knife

Patient Couch HelmetHelmet in treatment position

Shielding Radiation source

Collimator up closeCollimator up close

Helmet (collimators)

Stereotactic headframe

What is Cyberknife?What is Cyberknife?

Detailed view of CyberknifeDetailed view of Cyberknife

Linear accelerator

Robotic Arm

Radiation Exit point

Patient couch

CRT linear acceleratorCRT linear accelerator

A – Cathode

B – Conductive

coating

C – Anode

D – Phosphor

Coated screen

E – Electron Beams

F – Shadow mask

**A particle accelerator works basically the same way.

Brain Lab Novalis®

- 3 – 5.5 mm micro-multileaf collimator to conform to the shape of the target

- Dynamic conformal arc therapy

www.albertaradiosurgery.ca

Trials Ongoing/Planned

• Radiosurgery +/- WBXRT

• Doses of PCI in SCLC

• +/- PCI in NSCLC

• WBXRT +/- radiation sensitizer

• Avastin for GBM

• Neurogenic agents for XRT injury

Radiation Protection in Radiotherapy

Stereotactic proceduresStereotactic procedures

Target usually brain lesionsTarget usually brain lesions External head frame used to ensure External head frame used to ensure

accurate patient accurate patient positioningpositioning

Invasive orInvasive or Re-locatableRe-locatable

Radiation Protection in Radiotherapy

Image registrationImage registration Variety of systemsVariety of systems Many frame Many frame

attachments to attachments to allow for different allow for different diagnostic diagnostic modalities (MRI, modalities (MRI, CT, angiography)CT, angiography)

Radiation Protection in Radiotherapy

Image registrationImage registration

CT scan MRI

Leksell fiducial markers on both

Radiation Protection in Radiotherapy

Stereotactic proceduresStereotactic procedures

Spatial accuracy around 1mmSpatial accuracy around 1mm High dose single fraction (High dose single fraction (e.g.e.g. for for

arterio-venous malformations) = arterio-venous malformations) = stereotactic radiosurgery using an stereotactic radiosurgery using an invasively mounted head frameinvasively mounted head frame

Multiple fractions for tumour Multiple fractions for tumour treatment = stereotactic treatment = stereotactic radiotherapy using a re-locatable radiotherapy using a re-locatable head immobilisationhead immobilisation

Both systems MedTec

Stephan Eisenschenk, MD

UF LINAC Stereotactic Radiosurgery- Gantry

Radiation treatmentRadiation treatment

► Conventional radiation: Conventional radiation:

effective in< 20% of caseseffective in< 20% of cases► SRS: for small (Nidus<3cm) & deep SRS: for small (Nidus<3cm) & deep

AVMsAVMs► Radiation-induced endothelial cell Radiation-induced endothelial cell

proliferationproliferation→→Obliteration, thrombosisObliteration, thrombosis► Gamma knife/ LinacGamma knife/ Linac

► Non-invasive, gradual reduction of flowNon-invasive, gradual reduction of flow► Takes 1-3 yrs to work, limited to small Takes 1-3 yrs to work, limited to small

lesionlesion

Radiation Protection in Radiotherapy

GammaknifeGammaknife

Used for stereotactic brain irradiationsUsed for stereotactic brain irradiations 201 sources of Co-60 around a patients 201 sources of Co-60 around a patients

head - only sources which shall head - only sources which shall contribute to the irradiation are contribute to the irradiation are ‘unplugged’‘unplugged’

alignment crucialalignment crucial

Radiation Protection in Radiotherapy

Gamma knife head applicatorGamma knife head applicator

Radiation Protection in Radiotherapy

Patient in gamma knife collimator head Patient in gamma knife collimator head (from Ertl (from Ertl et al.et al. Phys. Med. Biol. 42 (1997) 2137) Phys. Med. Biol. 42 (1997) 2137)

Secondary Brain Tumors: Surgery

Galicich JH et al., Met. Brain tumors,In Wilkins: Neurosurgery, 597-61, 1985. November 2002

Secondary Brain Tumors: Radiotherapy

November 2002

030

x030 s

12 2.5 152

Secondary Brain Tumors: Radiotherapy

November 2002

Vincent Breton, cours ISIMA, 14/12/04

La radiothérapie est couramment utilisée pour traiter le cancer

2°) Treatment planning

Calculation ofdeposit dose on the tumor

(~1mn):A treatment plan is

developed using the images

1°) Obtain scanner slices images

The head is imaged using a MRI and/or CT scanner

3°) Radiotherapy treatment

Irradiation of the brain tumor with a

linear accelerator

Linear acceleratorLinear accelerator

Brain tumors: managementBrain tumors: management

seizures

symptomatic treatment: anticonvulsants

prophylactic treatment: controversial

- two randomized prospective studies (>170 pts with both primary and metastatic brain tumors) showed no significant benefit with prophylactic treatment

- possible exceptions: melanoma brain mets, pts w/ both brain mets and leptomeningeal mets (both groups 50-60% risk of seizures)

RTOG 0023: Results

Cardinale, Red J, 2006

FSRT MIGHT BENEFIT GROSS-TOTALLY RESECTED GBM

Although overall survivalwas not improved, there was a trend toward improvedsurvival with FSRT forpatients with total resection

Gamma Knife Radiosurgery• Indications

– Tumors (Benign & Malignant, Primary & Metastatic)– Arteriovenous malformations– Trigeminal neuralgia– Functional neurosurgery, to create lesions (controversial)

• Success Rate– Comparable success rate for tumors vs.

surgery/conventional radiation, with fewer side effects/morbidity/mortality

• Limitations– Tumors must be smaller (<3 cm.), and once a lesion is

made, it cannot be undone (irreversible)

• Side Effects/Complications– Rare, can include edema post-procedure

Gamma Knife Radiosurgery• The Principle:

– 201 cobalt-60 generated particles focus on one region, to deliver maximal energy to that region and minimal amount to surrounding brain tissue. Effects occur over weeks to months, although edema may be seen earlier. Patients are observed overnight, and then discharged.

http://www.sh.lsuhsc.edu/neurosurgery/gammaknife/gamma-knife/

Specialized Devices for SBRTSpecialized Devices for SBRT

Novalis Cyberknife Accelerator-based IGRT

(Trilogy, Synergy)

WFUBMC SBRTWFUBMC SBRT3-D Imaging Device3-D Imaging Device

Phillips PQ 5000 CT simulator

Single slice acquisition External lasers for

isocenter placement AcQSim software

WFUBMC SBRTWFUBMC SBRT

Varian 2100 SCX accelerator

6MV photon beam 120 leaf MLC Portal Vision

Metastatic Brain Tumor• History

– Rapidly progressive onset of symptoms (weeks vs. months) – Most common sources are LUNG, BREAST (in women), RENAL, & G.I. tract

• Diagnostic Imaging Studies– MRI: Tumor at grey-white matter

junction, usually associated with edema– Systemic work-up includes CT scan of

chest and abdomen• Diagnostic Laboratory Studies

– Liver function tests, CBC w/diff• Treatment

– For solitary lesion or less than 4 lesions all < 3 cm. – biopsy if undiagnosed, plus Gamma Knife

– For > 3 cm. tumor, surgery followed by WBRT

– For > 4 lesions, biopsy for diagnosis, plus whole brain radiation therapy.

• Prognosis: 7 – 12 mos.

http://www.neurobc.com/conditions/Brain_metastases.htm

Gamma Knife Radiosurgery• Indications

– Tumors (Benign & Malignant, Primary & Metastatic)– Arteriovenous malformations– Trigeminal neuralgia– Functional neurosurgery, to create lesions (controversial)

• Success Rate– Comparable success rate for tumors vs.

surgery/conventional radiation, with fewer side effects/morbidity/mortality

• Limitations– Tumors must be smaller (<3 cm.), and once a lesion is

made, it cannot be undone (irreversible)

• Side Effects/Complications– Rare, can include edema post-procedure

Gamma Knife Radiosurgery• The Principle:

– 201 cobalt-60 generated particles focus on one region, to deliver maximal energy to that region and minimal amount to surrounding brain tissue. Effects occur over weeks to months, although edema may be seen earlier. Patients are observed overnight, and then discharged.

http://www.sh.lsuhsc.edu/neurosurgery/gammaknife/gamma-knife/

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