Prostate Cancer G Bauman

A Cancer Care Ontario Partner

Achieving theAcheivable:

ProstateGlenn Bauman, MD

Associate Professor and Chair, Department of Oncology

London Regional Cancer ProgramUniversity of Western Ontario


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


The Future is a Moving Target…


Where we’ve been…


What we’ve learned….JCO 23:2005


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….


What we’ve learned…


EBXRT: Current Standard:3D - conformal


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


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

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m)

Prostate LeftProstate RightApex


Penile Bulb: anatomic marker


0

10

20

30

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1 2 3 4 5 6 7 8 9 10Patient number

Volu

me

(cm̂

3)CTMR3DUS

*

*

**

*

*


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


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


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


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


DVH Recommendations: PROFIT• Wall volumes; dosimetric definition• Rectal and Bladder wall: D50<53Gy and D30<71Gy

DVH Recommendations: RTOG P0126• lumen volumes; anatomic definition


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


Clinical Data Supporting Conformal XRT

(www.cancercare.on.ccopgi.on)


PollackIJROBPIn Press


Future Trend: IMRT


MSKCC81Gy; IMRT


“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


Inter-fraction variability in dose to

organ at risk (rectum)


5.9

TCP

NTCP


Strategy: Tracking fiducial markers


Strategy: Daily U/S localization


Strategy: Daily CT localization


Future Trend: BTV Definition

HypoxiaTumour Cells

Proliferation

fCT, PET/SPECT, fMRI

CT, MRI,US

Composite target

A Cancer Care Ontario PartnerDawson, Lancet Oncol, 7 2006


Future Trend: Target definition

IJROBP 63(4) 2005 1262-1269IJROBP 67(2) 2007 347-355


Future trend: IMRT for Nodal XRT


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 (%

)


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


• 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


IJRBOP 67(2): 2007 327-333; IJRBOP 67(2): 2007 334-341


Future trends: dose painting

Requirements:• biological imaging and multi-modality fusion• improved stereotaxis (robotic assisted?)• patient selection


Future Trend


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


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


Candidates•Margin positive•Seminal vesicle inv•Extracapsular ext


Future trend: GTV definition


Future trends: BTV (again!)


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)


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


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


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


http://www.youtube.com/watch?v=LQqq3e03EBQ


Thank You!

Prostate Cancer G Bauman

Health & Medicine

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