the role of cyberknife by dr. david spellberg

The Role of Cyberknife Stereotactic Body Radiation Therapy in the Treatment of

Localized Prostate CancerDavid M. Spellberg M.D., FACSNaples Urology Associates, P.A.

Naples, Florida

© Dr. David Spellberg

TREATMENT OPTIONS

• WATCHFUL WAITING• SURGERY• RADIATION THERAPY• CRYOTHERAPY• HIFU• PROTON• HORMONAL MANIPULATION• CHEMOTHERAPY• EXPERIMENTAL

© Dr. David Spellberg

RESEARCH

• INTERNET• LIBRARY• LOCAL CANCER SOCIETY• SUPPORT GROUPS• FAMILY/ FRIENDS

© Dr. David Spellberg

© Dr. David Spellberg

COMPLICATIONS OF TREATMENT

• INCONTINENCE• IMPOTENCE• EJACULATION DYSFUNCTION• BOWEL PROBLEMS• WORSENING OF OVERALL HEALTH

© Dr. David Spellberg

PATIENT DRIVEN

• NON-INVASIVE• MINIMAL SIDE EFFECTS• MINIMAL DISRUPTION OF LIFE• EFFICACY

© Dr. David Spellberg

• Frameless Radiosurgery

• Robotics

• Image Guidance• Advanced

Treatment Planning

CyberKnife Technology

© Dr. David Spellberg

© Dr. David Spellberg

• Precise control limits dose to the rectal wall and urethra

Prostate Radiosurgery

Image courtesy of San Diego CyberKnife Center

© Dr. David Spellberg

• Patient lies comfortably on the

couch while the CyberKnife robot moves, images and treats.

• Treatments typically last 1 hour

• Most patients require no sedation allowing them to depart at the completion of their treatment

CyberKnife Treatment Delivery

© Dr. David Spellberg

Radiation Options

Convenience Invasive Toxicity EfficacyIMRT Low No Mod HighLDR

BrachyTxHigh Yes X 1 Mod High

HDRBrachyTx

Moderate Yes X 2 Mod High

CK High No Very Low TBD© Dr. David Spellberg

SEQUENCE OF EVENTS

• PATHOLOGY REVIEW• CT/BS REVIEW• DISCUSSION OF TREATMENT

OPTIONS• FIDUCIAL PLACEMENT• CYBERKNIFE TREATMENT

© Dr. David Spellberg

FIDUCIAL PLACEMENT

• NPO• IV SEDATION• TRUS GUIDED TEMPLATE• ANTIBIOTICS

© Dr. David Spellberg

© Dr. David Spellberg

© Dr. David Spellberg

© Dr. David Spellberg

• Precise control limits dose to the rectal wall and urethra

• Automatic correction for target motion during treatment

Prostate Radiosurgery

Footage courtesy of St. Anthony’s Hospital

© Dr. David Spellberg

Accuray Confidential

© Dr. David Spellberg

• The prostate moves during treatment

240 seconds of Beam on time

5mm of motion

© Dr. David Spellberg

CyberKnife® Treatment of Prostate Cancer

© Dr. David Spellberg

Prostate PTV: gland expanded 5 mm in each direction except posteriorly where it is expanded 3

mm

© Dr. David Spellberg

BED Calculations• External Beam Radiation Therapy / HDR

– BED = nd [ 1 + (d/ α/β) ]• Low Dose Rate Permanent Decaying Implants

– BED = (Ro/ λ) { 1 + [ Ro/(μ+ λ)(α/β)] }• Definitions of parameters

n = # fractionsd = daily doseRo = initial dose rate of implantλ = radioactive decay constant = 0.693/T1/2

T1/2 = radioactive half-life of isotope μ = repair rate constant = 0.693/t1/2

t1/2 = tissue repair half-time© Dr. David Spellberg

Calculating BED For Low Risk CaP Monotherapy Treatment Regimens

• Biologically Equivalent Dose

• BED = D (1 + d/alpha beta ratio)

• D = total dose• d = dose/fraction• alpha/beta ratio = 1.5 for prostate 3 for late effects 10 for acute effects

• 81Gy IMRT/ 45fx / 9 weeks (BED 1.5 = 178.2, BED 3 = 129.6 )• HDR monoTx @ 9.5Gy X 4fx (BED 1.5 = 278.7, BED 3 = 158.3)• HDR monoTx @ 8.55Gy X 4fx (BED 1.5 = 229.1, BED 3 = 131.7)• HDR monoTx @ 7.25Gy X 6fx (BED 1.5 = 253.7, BED 3 = 148.6)• Cyberknife monoTx @ 7Gy X 5fx (BED 1.5 = 198.3, BED 3 = 116.7 ) • Cyberknife monoTx @ 7.25Gy X 5fx

(BED 1.5 = 211.5, BED 3 = 123.9 )© Dr. David Spellberg

Dose Calculations for Cyberknife Stereotactic Body Radiation Therapy

• For CK, one can fractionate the therapy yet remain convenient and non-invasive for the patient

• CK doses are most like HDR, since the dose/fraction, total doses and time factors are similar

• SHARP trial from Virginia Mason Hospital with good results (33.5Gy/5fx)

• Thus, since we have intermediate and long term results with HDR, CK appears to be a well founded treatment option

© Dr. David Spellberg

Basic Demographics• Ages 62 to 85• Stage cT1cNoMo to cT2bNoMo• All patients treated between 12/07/2004

and 12/31/2007• Total number of Patients = 213

© Dr. David Spellberg

Hormonal Therapy

• 186 Patients treated without Hormonal therapy

• 27 Patients treated with Neoadjuvant Hormonal Therapy

© Dr. David Spellberg

HistologyGleason grade 3 + 3 = 172 PatientsGleason grade 3 + 4 = 31 PatientsGleason grade 4 + 3 = 8 PatientsGleason grade 4 + 4 = 1 PatientGleason grade 5 + 4 = 1 Patient

© Dr. David Spellberg

Prostate Volumes

Range = 15.5cc to 109cc Mean initial volume = 45.7 cc Median initial volume = 46.1 cc

© Dr. David Spellberg

Prostate Cyberknife MonoTx Dose

Mean Dose = 3503 cGy (n=162) Median Dose = 3500 cGy Range = 3500cGy to 3755 cGy Number of Fractions = 5

© Dr. David Spellberg

Initial PSA’s

Range = 1.1 to 17.2 ng/ml Mean initial PSA = 5.87 ng/ml Median initial PSA = 5.75 ng/ml

© Dr. David Spellberg

PSA Response to Cyberknife

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iPSA 1 mo 3 mo 6 mo 9 mo 12 mo 15 mo 18 mo 21 mo 24 mo 36 mo

Mean PSA+HTx PSA-HTx PSA

© Dr. David Spellberg

Acute Toxicity

• Urinary hesitancy, urgency, frequency (Day 3-10)• Tenesmus/ rectal discomfort (Day 5-8)• Diarrhea (Day 5-8)

• Rx: Flomax Lomotil Decadron Anusol-HC supp.

© Dr. David Spellberg

Acute Toxicity Scoring(IPSS/RAS/SHIM)

• Baseline, days 2 and 5, post-treatment day 10, 1 month and 4 months

• Acute effects generally return to baseline by 1 months

• Urinary symptoms more marked in patients with IPSS baseline scores >20

• No urethral strictures/ persistent rectal bleeding observed

© Dr. David Spellberg

IPSS Scores After Cyberknife SBRT

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Overall Low (0-10) Mod(11-20) High(21-35)

Day 0Day 2Day 5Day 101 Month4 Month12 Month24 Month36 month

© Dr. David Spellberg

RAS and SHIM Scores after Cyberknife SBRT

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RAS Scores Overall SHIMScores

High SHIM(20-25)

Day 0Day 2Day 5Day 101 Month4 Month12 Month24 month36 month

© Dr. David Spellberg

Summary• Cyberknife is a new and innovative treatment

delivery technique for prostate cancer.• Cyberknife monotherapy produces an early decline of

PSA’s in low risk patients.• The acute toxicity of Cyberknife monotherapy is very

minimal compared to other radiation treatments.• Cyberknife therapy is a noninvasive and convenient

treatment option for patients with early stage prostate cancer.

• Prostate cancer patients treated with Cyberknife should continued to be enrolled and followed in research protocols, and the data collectively analyzed.

© Dr. David Spellberg