IntactProstateContouringGuide

eContourTeam

Youwanttocontour:IntactProstateWhatnow?

•  Findyourreferences–  RTOGnormalmalepelviscontouringatlas

•  h@ps://www.rtog.org/CoreLab/ContouringAtlases/MaleRTOGNormalPelvisAtlas.aspx

–  RTOGtrialswithcontouringdescripIonsforIMRTdescribedintheprotocol

•  RTOG0815•  RTOG0126

–  LinktoUCSDvideoofhowtocontourintactprostateslice-by-slice(websiteloginisfree)

*eContour.orgaimstobeyourone-stopshopforcontouringguidelines,withhyperlinkstoabovehigh-yieldreferences!

LeteContour.orghelpyou!

1.  SelectCASES

2.  Fromdropdowncaselist:GUàProstateàintact(notpost-prostatectomy)

3.  Reviewanatomy

4.  DrawOARs(rectumandpenilebulb)

5.  DrawtheGTVandCTV

6.  Addmargin/expansiontocreatefinalPTVfortreatmentplanning.

Quickreviewofbasicanatomyofprostate/pelvis

Penilebulb

Prostate

Bladder

Rectum

SeminalVesicle(SV)

Sacrum

ThefirststepincontouringaccuratelyistounderstandtheperInentanatomy.Onthissagi@alimage,theprostateisborderedbythebladdersuperiorly,thepubicsymphysisanteriorly,andtherectumposteriorly.

Pubicsymphysis

Coronal Axial

Baseofprostate

Apexofprostate

Oncoronalslice,thebladderissuperiortotheprostate.

Onanaxialslice,theprostateisborderedbythebladderandpubicsymphysisanteriorly,therectumposteriorly,andlevatorani/obturatorinternusmuscleslaterally.

Penilebulb

ProstateBladder

RectumObturator Internus

Levator Ani

Notallcasesofintactprostatecancerarecreatedequal!

GUàProstateàintact(notpost-prostatectomy)

–  NOTICEtheSTAGE/RISKSCORE!Thisisanintermediateriskcaseinwhichprostateandproximalseminalvesicle(SV)onlyaretreated.

–  PaIentswithlow-riskprostatecancerareoaenputonacAvesurveillance.However,iftreaIng,considerprostateonly(noSV).

–  PaIentswithhighriskprostatecancerraisemorecontouringquesIons…

•  Treatpelvicnodes?Dataiscontroversial.RTOG0924isongoing.•  Howmuchseminalvesicle(SV)totreat?Alsocontroversial.

DISCLAIMER:EachcaseisuniqueandrequiresdecisionmakingbasedonclinicaljudgmentofthetreaAngphysician.

Therearenoconsensusguidelines…butthereareseveralprotocolsdefiningtargetvolumesandPTVeContourusesthemostrecenttrials:RTOG0126andRTOG0815

StartwithOARs:Rectum

Levatorani

WearescrollingsuperiorlythroughtheCTslices

•  Contouringrectumcanhelpdefinetheposteriorborderoftheprostate.(SagiMalonnextslide)

•  Thelevatoraniisathinbroadmusclethatispartofthepelvicfloorwhichsurroundstheanalcanal(atthislevel).Theanalcanalisoaenincludedintherectalcontour.

•  Thelevatoranialsosupportstheprostate.

StartwithOARs:Rectum•  UsetheSAGITTALviewtomakesureyouarefollowingthecontouroftherectum!

Penilebulb

Prostate

Bladder

Rectum

SeminalVesicle(SV)

NextOAR:PenileBulbTheSAGITTALviewcanalsohelpidenIfythepenilebulb,asitisusuallyatthelevelofthebaseofthepenis.(Axialonnextslide)

Penilebulb

Prostate

Bladder

Rectum

SeminalVesicle(SV)

GUdiaphragm

Baseofpenis

NextOAR:Penilebulb

Penilebulb Baseofpenis

Thepenilebulbisoaenteardrop-shaped,locatedposteriortothebaseofthepenis.

Prostate

Rectum

Pubicsymphysis

ObturatorInternus

Now….contourtheGTV:Prostate

Thesearebloodvessels!Becarefulnottoincludetheseinyourprostatecontour.MRImakesthemeasiertosee.

TIP:ConsiderstarIngyourcontouratthemiddleoftheprostate(wherethebordersarewelldefined).

Levatorani

NOTE:Callingtheprostatea“GTV”isabitofamisnomer…theenAreprostateisnotgrosstumor.Butwewillgowithitpertheprotocols.

ContourtheGTV:Prostate

ProstateLevatorani Avoidincluding

levatoraniinyourprostatecontour.

Prostate

Rectum

Obturatorinternus

Levatorani

ContourtheGTV:Prostate

Levatoranicanhelpvisualizeapexofprostate,butavoidincludingitinyourprostatecontour.

ContourtheGTV:Prostate

ThemostinferiorprostatecontourshouldbeonesliceabovetheGUdiaphragm.

GenitourinaryDiaphragm(GUD)asalandmark?

Levatorani

Genitourinarydiaphragm=hourglassshape,locatedatconvergenceoflevatorani

Aka“urogenitaldiaphragm”outsideradonc

TheprostatesitsjustabovetheGUdiaphragmwhichsitsjustabovethepenilebulb.Problemis…theGUDishardtoseeonCT!AnMRIobtainedpriortotreatmentcanbefusedtothesimCTandaidcontourdelineaIon.MRIenhancessubtledifferencesbetweenthesesoaIssues.

ContourtheGTV:ProstateAlternaAveinferiorborder…Ifyoucan’tfindtheGUdiaphragm,justendyourprostate/GTVatleast0.7cmabovepenilebulb(ensuresPTVdoesnotoverlappenilebulb).

Penilebulb

Prostate

Bladder

Rectum

SeminalVesicle(SV)

Genitourinarydiaphragm

Prostatebase

SeminalVesicles

NowcontourtheSeminalVesicles

Theinferiorseminalvesicles(SVs)areinthesameaxialplanasthebaseoftheprostate–includeinCTV!

SuperiorborderofSV

Contourthetheproximal1cmoftheSV(proximalmeaningclosestoPROSTATE)…howdoIknow1cm?Nextslide…

WhentotreatSV?Thisisoaenbasedonclinicaljudgment(likelihoodofinvolvementbasedonextentofdisease,relaIverisk/benefitsincetreaIngSVincreasesdosetorectum).IntheRTOG0126,theproximal1cmisincludedinallpaIents.

MeasureSV(OpIon1)

Lookinlowerleaofyourscreenforthe“Z”coordinate.Scrollupordownoneslice,andthedifferenceistheCTslicethickness.ThenesImatenumberofslicestocontourby1cm/slicethickness.

MeasureSV(OpIon2)

Wewanttoincludeonlytheproximal1cm(meaningproximalorclosesttoprostate)ofSV.TIP:IntheSAGITTALview,usethemeasuringtooltochecktheverIcalextentofyourcontour.

GTV(prostate)+SV=CTV

Usethebooleantooltocombineprostate/GTVandSeminalVesicle(SV)intoasingleCTV.

TIP:ContouringprostateandSVseparatelyaffordsflexibilityincreaAngyourCTV(iecandecreasedosetoSVandboostprostateonlyifrectaldoseistoohigh).

AddamarginforPTV

RTOG0126andRTOG0815specify5-10mmformarginfromCTVtoPTV.ThisisoaeninsItuIonal,anddependsonimmobilizaIonanddailyimaging(forexample,kvX-rayswouldrequireabiggermarginthanCBCT).

Oaentheposteriormarginontherectumislesstoreduceriskoftoxicity,soweused7mmexcept5mmposteriorly.HowdoIaddanasymmetricmargin?(Seenextpage!)

AddamarginforPTV

“Marginforstructure”

NOTE:posteriormarginisless

Sagi@al Coronal

Alwayscheckyourfinalvolumesinsagi@alandcoronalviewstomakesureyouhavecontouredavolumethatmakessensein3dimensions!

FORFUN:OverlayRTDoseineContour

CTV

PTV

D95%

95%ofprescripIondose(79.2Gy)=75GyThisallowsustolookatthe95%isodoselinetoassesscoverageandconformality.

Oncethecontoursarecreated,aradiaIonplaniscreatedbytheDosimetrists.ThisstepisthenusuallythefirststepofradiaIonplanreview!

References

•  RTOGnormalmalepelviscontouringatlas– h@ps://www.rtog.org/CoreLab/ContouringAtlases/MaleRTOGNormalPelvisAtlas.aspx

•  RTOGtrialswithcontouringprotocols•  RTOG0815•  RTOG0126

•  LinktoUCSDvideoofhowtocontourintactprostateslice-by-slice(websiteloginisfree)

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