The treatment outcomes of oligometastatic colorectal cancer patients treated with stereotactic body radiation therapy: a multi-institutional analysis TROD 02-008

Abstract

Purpose/Objective(s):Stereotacticbodyradiotherapy(SBRT) is increasinglybeingusedtotreatoligometastaticcancers,buthigh-levelevidenceto supportpolicydecisions is lacking inpatientswithcolorectal carcinoma (CRC).Thepurposeof thisstudywastodeterminetheprognosticfactors forsurvival inoligometastaticcolorectalcancerpatientstreatedwithSBRT inamulticentricsetting. Materials/Methods:Theclinicaldataof437oligometastaticCRCpatients whoreceivedmetastasisdirectedtreatment(MDT)viaSBRTat18institutionsbetweenFebruary2007andFebruary2021werereviewedretrospectively.Patientseitherhaddenovooligometastasis (≤5metastases)at the timeofdiagnosisorhadoligometastaticrecurrencesduringfollow-up.All patientswere treatedwith the goal of curing theirmetastasis, and839 lesionswereirradiated. Results:Theaverageagewas61years(range;27-92years).Themajorityof patients(58.8%)hadcoloncarcinomawithasingleorganmetastasis(88.8 %).Theaveragenumberofmetastatic lesionswas2(range, 1-5).There were103patientswithlivermetastasis,222patientswithlungmetastasis, 58patientswithlymphnodemetastasis,60patientswithbonemetastasis, 32patientswithbrainmetastasis,and6patientswithotherorganmetastasis.BeforeRT,themedianCEAandCa-19-9levelswere5.16ng/mL(range: 0-8181.1ng/mL)and19.4(range:0.60-3693), respectively.AfterRT, the medianCEAandCa-19-9were5.00ng/mL(range,0.4-5693vng/mL)and 18(range,0-6577),respectively.Theaverageperiodoffollow-upwas15.2 months(range,0.3-91.5months).TheratesofOSandPFSaftertwoyears were 76.3% and 28.1%, respectively. Age (p<0.001), pre-RTCEA (p=0.006),pre-RTCa19-9(p=0.02),post-RTCEA(p=0.01), andpost-RT Ca19-9(p=0.02)wereallsignificantprognosticfactorsforOSinunivariate analysis.Age (HR=1.03, 95%CI, 1.01-1.04, p=0.004) andpre-RTCEA (HR=1.01,95%CI,1.00-1.02,p=0.04)wereindependentpredictorsofOS inmultivariateanalysis,whilepost-RTCEA(HR=1.93,95%CI,1.28-2.90, p=0.002)wasanindependentpredictorofPFS. Conclusion: SBRTtooligometastatic lesionswas foundtobeasafeand effective treatmentmodality forpatientswithcolorectal cancer. Survival waspredictedbyage, baselineCEA, and theCa19-9response toMDT. Additionalprospectivestudieswithlargercohortsarenecessarytovalidate ourfindings.