P A R A - A O R T I C

L Y M P H N O D E M E T A S T A S I S

CyberKnife® Team:

RadiationOncologists: DouglasWong,M.D.,Ph.D.,MPH

Urologist: GregRainwater,M.D.

Physicist: GeorgWeidlich,Ph.D.

CyberKnifeTherapists: JeffWallace,RTT ValerieCano,RTT

CyberKnifeCoordinator: LauraValenzuela,RN,BSN,OCN

CyberKnifeCenter: CommunityRegionalMedicalCenter Fresno,CA

CASE STUDY

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DEMOGRAPHICSSex: MaleAge: 66 yearsHistology: Metastatic Renal Cell Carcinoma

CLINICAL HISTORYReferred by: Medical OncologistPast Medical History: Stage IV renal cell carcinoma,

treated by radical nephrectomy one year prior

Case HistoryA66-year-oldmalewithahistoryofStageIVrenalcellcarcinoma,treatedwithaleftnephrectomyoneyearprior,presentedwithprogressiveleftflankpainandfindingsofalargeconfluentleftpara-aorticlymphnodemassonfollow-upimagingstudies.ACT-guidedbiopsyoftheleftpara-aorticlymphnoderevealedmetastaticcarcinomaconsistentwithhigh-graderenalcellcarcinoma.PET-CTscansrevealedfocalhypermetabolisminaregionofconfluentleftpara-aorticadenopathy,measuring9.0cmx4.5cmx5.0cm,withinvasionoftheadjacentpsoasmuscle(seeFigure1).Atthetimeoftheinitialdiagnosisoftherenalcellcarcinoma(StageIII,pT3N1M0)aradicalnephrectomyhadbeenperformedtoremovea2-cmlesioninvolvingthelowerpoleoftheleftkidneyanda5-cmmassinthemid-kidneythatextendedfocallythroughtheleftrenalcapsuleinvolvingtheperinephricfat.Lymphnodesamplingatthetimeofnephrectomyrevealedoneoffourpara-aorticlymphnodespositiveformetastaticrenalcellcarcinoma.AtthetimeadecisionwasmadetofollowthesefindingswithPET-CTimaging.

CyberKnife® Treatment Rationale Renalcellcarcinomahastypicallybeentreatedprimarilywithsurgicalresectionandhasnotrespondedwelltotreatmentbyconventionalradiationtherapybecauseoftheinabilitytodeliverhigh,tumoricidaldosesofradiationtothetumorsafely.Thelocationofthislargepara-aorticmassaswellasitsintimaterelationshipwithadjacentvasculaturemadesurgicalresectionanunlikelyoptioninthiscase.Treatmentwasattemptedwithmultipletyrosinekinaseinhibitorstoshrinkthetumorbutthistherapywasnottolerated.CyberKnife®radiosurgerywaschosentoallowdeliveryofhighdosesofradiationinaconformalmannertosparetheadjacentcriticalstructureswhilestilldeliveringdoseshighenoughtoachievetumorcontrol.TheCyberKnifeSystemhassuccessfullytreatedprimaryrenalcellcarcinomas,1aswellasspinalmetastasesfromrenalcellcarcinoma,2whilepreservingthesurroundingtissueandcriticalstructures.

Figure 1. Pretreatment PET-CT scans revealed high FDG uptake in the region of the confluent left para-aortic adenopathy measuring 9.0 cm x 4.5 cm x 5.0 cm, with invasion of the adjacent psoas muscle.

Planning ProcessThepatientwaspreparedfortreatmentplanningbyimplantingfivefiducialsintotheperipheryofthetumor.Avaclockbagandkneespongewereusedforimmobilization.ContoursoftheGTV,PTV,rightkidney,adjacentbowelandspinalcanalweregeneratedontheimagingstudies.Toprotectadjacentsmallbowel,thePTVwasdeliberatelymadesmallerthantheGTV,acceptingadosegradientacrosstheanteriorrimoftheGTV.AconformaltreatmentplanwasdevelopedusingtheMultiPlan®TreatmentPlanningSystemtocover97.7%ofthePTVand86.2%oftheGTV(seeFigure2).

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Treatment Volume: PTV=99.9 cm3

Imaging Technique(s): CTRx Dose & Isodose: 24 Gy to 80%Dose and Fractions: 8 Gy x 3 fractionsNumber of Beams: 174

Number of Fiducials: 5Treatment Time: 120 minutes/fractionTracking Method: SynchronyCollimator(s): 25 mmTumor Coverage: PTV=97.7%

TREATMENT DETAILS

Figure 2. Left panel shows an axial view of the treatment plan developed using the MultiPlan® System. The 80% prescription isodose line is shown in green. Note high conformality and sparing of critical structures. The right panel shows a 3-D rendering of treatment beams as selected by the optimization algorithm.

Treatment DeliveryThepatientreceived24Gydeliveredinthreefractionsof8Gyoverthreedays.Thetreatmentwasdeliveredtoavolumeof99.9cm3(PTV),using174beamsanda25-mmcollimator.The80%isodoselineprovided97.7%coverageofthePTV.Thethreeoutpatienttreatmentswereaccompaniedbymildnauseathatwasrelievedwithoralcompazine.

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CYBERKNIFE CENTER AT COMMUNITY REGIONAL MEDICAL CENTERThe CyberKnife Center at Community Regional Medical Center in Fresno, California entered clinical service in the fall of 2005. Community’s cancer program is one of the few in California with teaching-hospital level accreditation from the American College of Surgeons (ACOS) Commission on Cancer. At Community Regional in downtown Fresno we operate the only combined burn and Level 1 trauma center between Sacramento to Los Angeles, the only high-risk pregnancy unit in the region, and the state’s largest and second busiest emergency department.

To contact us please visit our website at www.communitymedical.org or call (559) 447-3591.

• TwomonthsfollowingCyberKnife®treatment,aPETscandemonstratedadecreaseinsizeofthepara-aorticmassanddecreasedSUVfrom7.5to2.2(seeFigure3)

• FourmonthsafterCyberKnifetreatment,arepeatPETscanrevealedfurtherdecreaseinSUV(from2.2to1.7)withinadecreasingleftpara-aorticnodalmass;nonewareasofPETpositivitySUVuptakewerenoted

• FourteenmonthsafterCyberKnifetreatment,aPET-CTscanrevealedcontinueddecreaseinthesizeoftheleftpara-aorticmasswithSUVof2.3(Figure4);thepatientremainspain-freeandenjoysnormalactivitieswithoutlimitation

References1. Ponsky LE, Crownover RL, Rosen MJ, et al. Initial evaluation of Cyberknife technology for extracorporeal renal tissue ablation. Urology 2003;61:498-501.2. Gerszten PC, Burton SA, Ozhasoglu C, et al. Stereotactic radiosurgery for spinal metastases from renal cell carcinoma. J Neurosurg Spine 2005;3:288-295.

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Conclusion and CyberKnife® Advantages• ThispatienthadanexcellentinitialoutcomewiththeCyberKnifeSystemforthetreatmentofametastaticrenalcellcarcinomatoapara-aorticlymphnode

• TheCyberKnifeSystemprovidedaconvenientandminimallyinvasivetreatmentoptionforpatientswithmetastasistopara-aorticlymphnodes

Figure 3. PET-CT scans obtained 2 months after CyberKnife treatment demonstrating a significant reduction in the FDG uptake in the region of the confluent left para-aortic adenopathy.

Figure 4. PET-CT scans obtained 14 months after CyberKnife treatment demonstrating a continued reduction in the FDG uptake in the region of the confluent left para-aortic adenopathy.