AIM:Tostudyhowlymphnodemetastasis(LNM)riskisstratifiedinundifferentiated-typeearlygastriccancer(undiff-EGC)dependentoncombinationsofriskfactors.METHODS:Fivehundredandsixty-sevencaseswithundiff-EGCundergoinggastrectomywithlymphadenectomywereexaminedretrospectively.Usingclinicopathologicalfactorsofpatientage,location,size,anendoscopicmacroscopictumorform,ulceration,depth,histology,lymphaticinvolvement(LI)andvenousinvolvement(VI),LNMriskwasexaminedandstratifiedbyconventionalstatisticalanalysisanddatamininganalysis.RESULTS:LNMwaspositivein44of567cases(7.8%).Univariateanalysisrevealed>2cm,protrusion,submucosal(sm),mixedtype,LIandVIassignificantprognosticfactorsand>2cmandLI-positivewereindependentfactorsbymultivariateanalysis.InpreoperativelyevaluablefactorsexcludingLVI,smand>2cmwereindependentfactors.Accordingtothedepthandsize,caseswerecategorizedintothelow-riskgroup[mand≤2cm,0%(LNMincidence)],themoderateriskgroup(mand>2cm,5.6%;andsmand≤2cm,6.0%),andthehigh-riskgroup(smand>2cm,19.3%).Ontheotherhand,LNMoccurredin1.4%inallLI-negativecases,greatlylowerthan28.2%inallLI-positivecases,andLNMincidencewaslowinLInegativecaseseveninthemoderate-andhigh-riskgroups.CONCLUSION:LNM-relatedfactorsinundiff-EGCweredepthandsizepreoperativelywhilethosewereLIandsizepostoperatively.Amongthesefactors,LIwasthemostsignificantlycorrelatedfactor.
