A Cancer Care Ontario Partner
Achieving theAcheivable:
ProstateGlenn Bauman, MD
Associate Professor and Chair, Department of Oncology
London Regional Cancer ProgramUniversity of Western Ontario
A Cancer Care Ontario Partner
Objectives
• We’re we’ve been• What we’ve learned• What we should do • Where we should go
• External beam• Brachytherapy• Postoperative radiotherapy• Related issues
A Cancer Care Ontario Partner
Risk stratification• Low risk
• T1-T2; PSA<10; Gleason<6• (% cores or PSA velocity*)
• Intermediate risk• T1/T2; PSA<20; Gleason <7; not otherwise low risk• (% cores or PSA velocity*)
• High risk• PSA >20 or T3 or Gleason >8;
>50% cores positive or PSA velocity >2ng/ml/yr upstages*
What we’ve learned….
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CT simulation• Simple immobilization sufficient• Patient instructions for bladder/rectum filling• Minimize iatrogenic perturbations• Flag “outliers” (rectal volume or CSA)
Contouring conventions (prostate + OAR)• Modality dependent• Apex and base definition• Seminal vesicles and nodes• Wall vs. solid OAR
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Sample patient data: Marker Motion (Ant/Post, Sup/Inf) from Weekly Port Film
22-Aug
12-Aug7-Aug
Urethrogram
17-Jul
31-Jul
12-Jul
28-Aug
12-Jul
22-Aug
17-Jul
28-Aug
31-Jul
Urethrogram
7-Aug
12-Aug
31-Jul
12-Jul
7-Aug17-Jul 28-Aug
Urethrogram
12-Aug22-Aug
-1
-0.5
0
0.5
1
1.5
-3.5 -3 -2.5 -2 -1.5 -1 -0.5 0Sup/Inf direction (cm)
Post
/Ant
dire
ctio
n (c
m)
Prostate LeftProstate RightApex
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0
10
20
30
40
50
60
1 2 3 4 5 6 7 8 9 10Patient number
Volu
me
(cm̂
3)CTMR3DUS
*
*
**
*
*
A Cancer Care Ontario Partner
GTV Delineation: SummaryTechnique Advantages Limitations
CT Available/simple contouring (base/apex)
CT+ markers Apex; IG Invasive/base delineation
CT+ contrast Apex; base Systemic error
2D TRUS Contouring easy “not fuseable”
3D Ext US “fuseable”, IG inter-observer error
MRI “fuseable” Availability; not Rx
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CTSIM Prep• BM prior
• 500cc fluids• no urethrogram
Persistent large rectal volume orHypofx: IGXRT
OARs and GTVsPTVs generated; +/- pelvic fields
1cm margin; 0.7mm post if IGXRT95% isodose coverage of PTV; 73Gy/35
SIB class solution or 3DCRT plan (IMRT if dose constraints not met)
CTSIM; if large rectal volumerectal tube or bathroom and reCT
Planning: One approach
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10 Gy AP/PA 10 Gy R/L LAT 3 Gy/R/L LAT
25 Gy AP/PA 25 Gy R/L LAT
Phase I:50Gy/25
Phase II:23Gy/10
Planning: One approach73Gy/35 fraction
75-77Gy BED
SIB selected based on % overlaps
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EBXRT Minimum Standards
• Every patient planned• 3D dose distribution and DVH• PTV and OAR DVH constraint based
• Choose a class solution and stick with it• 4-6 field 3DCRT
• Motion management strategy• Minimum dose BED > 74 Gy• PTV margins 1.0cm; 0.5-0.7 posterior
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DVH Recommendations: PROFIT• Wall volumes; dosimetric definition• Rectal and Bladder wall: D50<53Gy and D30<71Gy
DVH Recommendations: RTOG P0126• lumen volumes; anatomic definition
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30 40 50 60 70 80
“Dosimetric”
Anatomic
0%10%20%30%40%50%60%70%80%90%
100%
0 20 40 60 80 100
Effects of variation of
contouring on rectal DVH
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“If you can’t see it, you can’t hit it.If you can’t hit it, you can’t cure it”
H.E. Johns or W. Powers
“If it’s moving, you can’t hit it.If you can’t hit it, you can’t cure it”
J. Battista
Future Trend: 4D Adaptive RT
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Future Trend: BTV Definition
HypoxiaTumour Cells
Proliferation
fCT, PET/SPECT, fMRI
CT, MRI,US
Composite target
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Future Trend: Target definition
IJROBP 63(4) 2005 1262-1269IJROBP 67(2) 2007 347-355
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Future trend: Hypofractionation
* Fowler J, et al. Int J Radiat Oncol Biol Phys 2003;56:1093-1104.
Iso-late-complicationsTum
or C
ontr
ol P
roba
bilit
y (%
)
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Standards: Prostate I125
• Prostate Volume < 50 cc• Clinical Stage T1c or T2a• PSA < 10• Gleason Score < 6• No Nodal or distant metastases• No previous TURP
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• Ultrasound Volume Study • Pubic Arch Interference Assessment• Pre-plan: 145Gy to periphery of prostate• Ordering I-125 seeds and calibration• Needle loading• Ultrasound guided Implantation• CT post-planning
Standards: Prostate I125
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Future trends: dose painting
Requirements:• biological imaging and multi-modality fusion• improved stereotaxis (robotic assisted?)• patient selection
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Future trends: HDR Prostate Brachytherapy• int - high risk prostate
cancer• Utilizes temporary
catheters; u/s guidance; perineal template
• Iridium 192 delivers dose in minutes
• Usually combined with EBXRT (4-5 weeks)
• Invasive, hospitalization overnight
• 1-3 fractions
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Postoperative/Salvage Radiation
Postoperative: • 3 RCT supporting adjuvant radiation• pT3 or margin positiveSalvage• Case series only (Stephenson, JAMA)• Margin positive, PSA < 2.0, post RP kinetics
CTSIM; 60-66Gy/30=33; 3DCRT
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Radical prostatectomy
Assess need for RT
Uncertain groupImmediate RT group
Trial follow-up
RANDOMISEImmediately after surgery
RANDOMISE
Outcome measures
RT + no AD RT + short AD RT + long AD
Trial follow-up
Monitor on trial
Immediate RT
Deferred RT
Time
All Groups
RANDOMISE
Immediately after surgery
RT + no AD RT + short AD RT + long AD
RADICALS randomised comparisons: Flow diagram
At rising PSA
Deferred RT group (Monitored off trial, now PSA rising)
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What is needed?
• Common prep, contouring and DVH conventions• Multi-modality GTV definition (U/S or MRI)• IMRT enabled planning and LINACS• Efficient IMRT class solutions and QA/QC• Image guidance requirements:
• CL-PTV: repeat CTSIM and dosimetry capacity• CT: CB or MVCT Unit• U/S: US at LINAC and CTSIM• Seed: Marker placement (radiology)
• RT training: image interpretation; action levels; correction
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What else is needed – long term?• Better predictors of toxicity/common databases• Biological and functional multi-modality imaging• Complete ongoing RCT
• Dose escalation and hypofractionation
• New RCT• Multimodality (LDR/HDR/CTX/Sx)
• A new paradigm?• “Prostate Lumpectomy” + regional XRT
• Patient decision aids• EPR enabled follow-up
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Changes in CaP XRT• 66-70Gy• 4 field; blocks• Fluoroscopic • DRE
• 3D CRT• LDR• Hypofx (Part I)• Models
• MLC• TPS• CTS• RVS• Fiducials
• BED >78Gy• IGXRT• IMRT
• Multi-modal• BTV optimization• Prostate SRT• Gating
• Multi-modal imaging• Real time IGXRT• Multi-modal TPS• BTV TPS
• BED > 74 Gy• 4-6 fields; 3DCRT• CTSIM• Risk stratified, bDFS
• IGXRT• HDR• Dose escalation• Hypofx (Part II)
• dMLC• EPI/US/CBCT/MVCT• MR SIM/CT-US SIM
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