StereotacticCyberknife based radiotherapy

in Liege

introductionpossible dosimetric comparisons

?

Nicolas JansenApril 2011

The pendulum swings …

• From simple to complex• From medium dose to ultra high dose• From large volumes to small volumes• From unefficient to very efficient ?• From surgery to radiotherapy ??• From cheap to expensive ??? (or …)

The pendulum swings …

Acta Oncol. 1995;34(6):861-70. Stereotactic high dose fraction radiation therapy of extracranial tumors using an accelerator. Clinical experience of the first thirty-one patients.Blomgren H et al. Karolinska Hospital, Stockholm, Sweden

Int J Radiat Oncol Biol Phys. 2000 Sep 1;48(2):449-57. Megavoltage CT-assisted stereotactic radiosurgery for thoracic tumors: original research in the treatment of thoracic neoplasms.Nakagawa K et al. University of Tokyo, Tokyo, Japan

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Publications onstereotactic lungradiotherapy

Example for lung SRS …

InBelgium ?

Curr Probl Cancer. 2003 Jan-Feb;27(1):60-3.New potentials of radiotherapy in non-small cell lung cancer: stereotactic therapy and IMRT. Van Houtte P. Radiation Department, Institute Jules Bordet, Brussel

J Vasc Interv Radiol. 2005 Jan;16(1):51-6. Percutaneous placement of marking coils before stereotactic radiation therapy of malignant lung lesions. de Mey J et al.Department of Radiology, UZ Brussel

Cancer Radiother. 2010 Oct;14(6-7):446-54 Gating and tracking, 4D in thoracic tumours. Verellen D et al. Department of Radiotherapy, UZ Brussel

Int J Radiat Oncol Biol Phys. 2010 Aug 12. Prospective, Risk-Adapted Strategy of Stereotactic Body Radiotherapy for Early-Stage Non-Small-Cell Lung Cancer: Results of a Phase II Trial. Bral S, et al. Department of Radiotherapy, UZ Brussel

1990-1995 1996-2000 2001-2005 2006-2010 2011-2015

Belgian RT centers or sattelites

Centers doing stereotactic lungradiotherapy

Centers doing full tracking basedand 4D adapted stereotactic lungradiotherapy

Example for lung SRS …

VUB

• Assessment of the uncertainties in dose

delivery of a commercial system for

linac-based stereotactic radiosurgery -

Verellen D, et al. - Int J Radiat Oncol Biol

Phys. 1999-5 1;44(2):421-33

Are there any quality differences in stereotactic radiotherapy approaches ?

• Differences based on …– Experience– Internal workflow and quality control– Technical differences in treatment delivery

system• Beam characteristics• Tracking capabilities• …

What are the different systems for stereotactic radiotherapy delivery ?

• Stereotactic placement of sources for prostate brachytherapy

• (Very conformal treatments)• Classical linac based (Novalis)• Tomotherapy based systems• Purpose build stereotactic devices

with inherent 4D capabilities– Vero– Cyberknife

• Comparison of stereotactic approaches

– Ideally : clinical outcome based (long time effort)• Narrow comparison : between stereotactic systems• Wider comparison : Stereotactic radiotherapy versus …

protontherapy, surgery, targeted systemic therapies, …

– Dosimetric comparison• Narrow comparison : between stereotactic devices• Wider comparison : stereotactic systems relative to a

more ‘classical approach’ to be able to justify the stereotactic approach

Comparing radiotherapy approaches

• Clinical outcome

• Dosimetric

• Time

• Cost

• Availability

• Acceptability

Comparing radiotherapy approaches

• Clinical outcome

• Dosimetric

• Time

• Cost

• Availability

• Acceptability

Dosimetric comparison

• How to compare ?– For each OAR : different DVH parameters– For the PTV : the coverage, … (indices)

• But cheating is possible– (Forgetting) margin management– Look only at high dose regions– Non standardised planning goals and efforts

Dosimetric comparison

• How to compare plan results ?– DVH comparison

• Curve form• Key DVH parameters

– DVH indices– Dose distribution itself

• (not to loose geographical information)

Dosimetric comparison

• How to compare plan results ?– DVH comparison

• Curve form• Key DVH parameters

– DVH indices– Dose distribution itself

• (not to loose geographical information)

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Structure 1,plan 1

Structure 1,plan 2

Dosimetric comparison

• How to compare plan results ?– DVH comparison

• Curve form• Key DVH parameters

– DVH indices– Dose distribution itself

• (not to loose geographical information)

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Structure 1,plan 1

Structure 1,plan 2

Dosimetric comparison• DVH derived parameters

– Validated for stereotatic treatments ?– Are they clinically relevant ?

• Which ones do we want to analyse ?– Single point constraints/limits

• Vx• Dx

– Mathematically derived parameters• CI, DHI,

– Tumor response models• Lyman NTCP model• Local Radiation Response - Organ Functional Reserve

Models

Dosimetric comparison• DVH derived parameters

– Validated for stereotatic treatments ?– Are they clinically relevant ?

• Which ones do we want to analyse ?– Single point constraints/limits

• Vx• Dx

– Mathematically derived parameters• CI, DHI,

– Tumor response models• Lyman NTCP model• Local Radiation Response - Organ Functional Reserve

Models

DVH parameters

• CI :– V ref isodose / V target volume

– Conformity index– A ratio of VOLUMES– Ideally CI = 1– RTOG radiosurgery quality guidelines :

• CI = 1.0 to 2.0• CI = 0.9 to 1.0 or 2.0 to 2.5 : minor deviation• CI < 0.9 or CI > 2.5 : major deviation

DVH parameters

• CI :– Min isodose surrounding the target / Reference isodose

– Coverage index– A ratio of DOSES– Ideally 100%– RTOG radiosurgery quality guidelines :

• CI > 90% : adequate• CI 80% to 90% : minor deviation• CI < 80% : major deviation

DVH parameters

• HI :– Max isodose in the target / Reference isodose

– Homogeneity Index– A ratio of DOSES– Ideally HI = 1 ? NO, if hot spots are inside the GTV

– RTOG radiosurgery quality guidelines : • HI 1.0 to 2.0 : adequate• HI 2.0 to 2.5 : minor deviation• HI > 2.5 : major deviation

Dosimetric comparison

• Pre-analysis standardisation– Equal image set used– Identical GTV-CTV– Identical dose and fractionation

• But …– Not all systems require the same immobilisation– Different treatment execution errors and different

tracking parameters can induce different … margins

Margins …• Reflect the imprecisions and errors of the whole

treatment preparation and delivery chain

• GTV to CTV : should be identical

• CTV to PTV : to be re analysed for each technique

• Are a source of … errors– Unrealistic margins– Should be adapted to … new imprecisions

• Marker tracking• …

Ablative dose, no ablative results

• If the dose is ablativen why is the LC after the treatment not 100%

– The staging was incomplete or inaccurate

– The dose is not ablative because of radioresistance

– Geographical miss

What do we know about comparisons in stereotactic radiotherapy ?

• First data

– Dosimetric comparison of stereotactic radiosurgery to intensity modulated radiotherapy - Kramer BA, Wazer DE, Engler MJ, Tsai JS, Ling MN - Radiat Oncol Investig. 1998;6(1):18-25.

– Dosimetric comparison of stereotactic body radiotherapy in different respiration conditions: a modeling study - Kontrisova K, Stock M, Dieckmann K, Bogner J, Pötter R, Georg D - Radiother Oncol. 2006 Oct;81(1):97-104

– Dosimetric comparison of linear accelerator-based stereotactic radiosurgery systems - Sharma SD, Kumar S, Dagaonkar SS, Bisht G, Dayanand S, Devi R, Deshpande SS, Chaudhary S, Bhatt BC, Kannan S - J Med Phys. 2007 Jan;32(1):18-23.

What do we know about comparisons ?• Not cyberknife related : hot topic last 6 months!

– Cost-Effectiveness Analysis of Stereotactic Body Radiotherapy and Radiofrequency Ablation for Medically Inoperable, Early-Stage Non-Small Cell Lung Cancer - Sher DJ, Wee JO, Punglia RS - Int J Radiat Oncol Biol Phys. 2011 Feb 10

– Comparison of stereotactic brachytherapy (125 iodine seeds) with stereotactic radiosurgery (LINAC) for the treatment of singular cerebral metastases - Ruge MI, Kocher M, Maarouf M, Hamisch C, Treuer H, Voges J, Sturm V - Strahlenther Onkol. 2011 Jan;187(1):7-14

– Stereotactic radiotherapy for peripheral lung tumors: a comparison of volumetric modulated arc therapy with 3 other delivery techniques - Ong CL, Verbakel WF, Cuijpers JP, Slotman BJ, Lagerwaard FJ, Senan S - Radiother Oncol. 2010 Dec;97(3):437-42

– Randomised phase I/II study to evaluate carbon ion radiotherapy versus fractionated stereotactic radiotherapy in patients with recurrent or progressive gliomas: the CINDERELLA trial - Combs SE, Burkholder I, Edler L, Rieken S, Habermehl D, Jäkel O, Haberer T, Haselmann R, Unterberg A, Wick W, Debus J - BMC Cancer. 2010 Oct 6;10:533

– Dose-volume comparison of proton radiotherapy and stereotactic body radiotherapy for non-small-cell lung cancer - Kadoya N, Obata Y, Kato T, Kagiya M, Nakamura T, Tomoda T, Takada A, Takayama K, Fuwa N - Int J Radiat Oncol Biol Phys. 2011 Mar 15;79(4):1225-31

– Dosimetric comparison of intensity-modulated stereotactic radiotherapy with other stereotactic techniques for locally recurrent nasopharyngeal carcinoma - Kung SW, Wu VW, Kam MK, Leung SF, Yu BK, Ngai DY, Wong SC, Chan AT - Int J Radiat Oncol Biol Phys. 2011 Jan 1;79(1):71-9.

What do we know about comparisons ?• Cyberknife related

– A dosimetric comparison between Gamma Knife and CyberKnife treatment plans for trigeminal neuralgia - Descovich M, Sneed PK, Barbaro NM, McDermott MW, Chuang CF, Barani IJ, Nakamura JL, Lijun M - J Neurosurg. 2010 Dec;113 Suppl:199-206 (University of California, San Francisco)

– A dosimetric comparison of stereotactic body radiation therapy techniques for lung cancer: robotic versus conventional linac-based systems - Ding C, Chang CH, Haslam J, Timmerman R, Solberg T - J Appl Clin Med Phys. 2010 Jun 29;11(3):3223 (University of Texas Southwestern Medical Center, Dallas)

– Intracranial radiosurgery in the Netherlands. A planning comparison of available systems with regard to physical aspects and workload - Schoonbeek A, Monshouwer R, Hanssens P, Raaijmakers E, Nowak P, Marijnissen JP, Lagerwaard FJ, Cuijpers JP, Vonk EJ, van der Maazen RW - Technol Cancer Res Treat. 2010 Jun;9(3):279-90 (Radboud University Nijmegen Medical Centre, Nijmegen)

– Quality of radiosurgery for single brain metastases with respect to treatment technology: a matched-pair analysis - Wowra B, Muacevic A, Tonn JC. - J Neurooncol. 2009 Aug;94(1):69-77 –(European CyberKnife Center Munich)

– Comparison of advanced irradiation techniques with photons for benign intracranial tumours - Cozzi L, Clivio A, Bauman G, Cora S, Nicolini G, Pellegrini R, Vanetti E, Yartsev S, Fogliata A - Radiother Oncol. 2006 Aug;80(2):268-73 (Oncology Institute of Southern Switzerland, Medical Physics, Bellinzona, Switzerland )

– Dosimetric comparison of CyberKnife with other radiosurgical modalities for an ellipsoidal target - Yu C, Jozsef G, Apuzzo ML, Petrovich Z - Neurosurgery. 2003 Nov;53(5):1155-62 (University of Southern California, Los Angeles)

A dosimetric comparison between Gamma Knife and CyberKnife treatment plans for trigeminal neuralgia - Descovich M, Sneed PK, Barbaro NM, McDermott

MW, Chuang CF, Barani IJ, Nakamura JL, Lijun M - J Neurosurg. 2010 Dec;113 Suppl:199-206 (University of California, San Francisco)

Discussion : what treatment planning efforts have been done ?Less beams in CK !

A dosimetric comparison of stereotactic body radiation therapy techniques for lung cancer: robotic versus conventional linac-based systems - Ding C, Chang

CH, Haslam J, Timmerman R, Solberg T - J Appl Clin Med Phys. 2010 Jun 29;11(3):3223 (University of Texas Southwestern Medical Center, Dallas)

• n=8 / common contours / 3x20 Gy

• 4D CT scan → MIP creation

• PTV 3D created, also PTV 4D

A 4D CT scanning is performed.

A 3D conformal linac- SBRT plan is designed on ITV and corresponding PTV 3D.

A deformable registration method is then applied to obtain the 4D cumulative dose distribution.

GTV and PTV 4D are contoured on the 50% phase of 4D CT images, which corresponds to the maximum exhalation.

The 50% phase of 4D CT images and contour sets of GTV and PTV 4D are sent to CyberKnife system for Synchrony planning.

CI = conformity index =the ratio of the tissue volume receiving the prescription isodose or moreto the tumor volume

Intracranial radiosurgery in the Netherlands. A planning comparison of available systems with regard to physical aspects and workload - Schoonbeek A, Monshouwer R,

Hanssens P, Raaijmakers E, Nowak P, Marijnissen JP, Lagerwaard FJ, Cuijpers JP, Vonk EJ, van der Maazen RW - Technol Cancer Res Treat. 2010 Jun;9(3):279-90 (Radboud University

Nijmegen Medical Centre, Nijmegen)

• 5 systems– CK

– Gammaknife

– Novalis 3 mm leafs

– Tomotherapy

– Linac 10 mm leafs

• GTV + 2 mm = PTV (fixed for all systems)• N = 5 patients (skull base tumors)

– 3 size levels

• Dose prescribed : 80% isodose surrounding the PTV

• 3 target volumes– 0.1 ml : no system can respect the

conformality index (all >3.0)– 0.5 ml : better for CK, GK– 1.0 ml : all systems respect RTOG

Quality of radiosurgery for single brain metastases with respect to treatment technology: a matched-pair analysis - Wowra B, Muacevic A, Tonn JC. - J Neurooncol. 2009 Aug;94(1):69-77 –(European CyberKnife Center Munich)

• With a matched-pair analysis we were able to prove that identical quality of clinical results in single brain metastases can be achieved with the GK and the CK.

• Furthermore we could show that the radiosurgical dose can be better tailored to the target with the CK than with the GK.

• This result, a more homogeneous dose distribution, and a lower peripheral dose represent an advantage of the CK in regard of the radiation protection

Comparison of advanced irradiation techniques with photons for benign intracranial tumours - Cozzi L, Clivio A, Bauman G, Cora S, Nicolini G, Pellegrini R, Vanetti E, Yartsev S,

Fogliata A - Radiother Oncol. 2006 Aug;80(2):268-73 (Oncology Institute of Southern Switzerland, Medical Physics, Bellinzona, Switzerland )

AMOA = intensity modulated arc therapyHT = helical thomotherapy

Dosimetric comparison of CyberKnife with other radiosurgical modalities for an ellipsoidal target - Yu C, Jozsef G, Apuzzo ML, Petrovich Z - Neurosurgery.

2003 Nov;53(5):1155-62 (University of Southern California, Los Angeles)