简介：Objective:Survivalandtreatmentofpatientswithmicroinvasivebreastcancer(MIBC)remaincontroversial.Inthispaper,weevaluatedwhetheradjuvantchemotherapyisnecessaryforpatientswithMIBCtoidentifyriskfactorsinfluencingitsprognosisanddecidetheindicationforadjuvantchemotherapy.Methods:Inthisretrospectivestudy,108patientswithMIBCwererecruitedaccordingtoseventheditionofthestagingmanualoftheAmericanJointCommitteeonCancer(AJCC).Thesubjectsweredividedintochemotherapyandnon-chemotherapygroups.Wecomparedthe5-yeardisease-freesurvival(DFS)andoverallsurvival(OS)ratesbetweengroups.Furthermore,weanalyzedthefactorsrelatedtoprognosisforpatientswithMIBCusingunivariateandmultivariateanalyses.Wealsoevaluatedtheimpactofadjuvantchemotherapyontheprognosticfactorsbysubgroupanalysisaftermedianfollow-uptimeof33months(13-104months).Results:The5-yearDFSandOSratesforthechemotherapygroupwere93.7%and97.5%,whereasthoseforthenonchemotherapygroupwere89.7%and100%.Resultsindicatethat5-yearDFSwassuperior,butOSwasinferior,intheformergroupcomparedwiththelattergroup.However,nostatisticalsignificancewasobservedinthe5-yearDFS(P=0.223)orOS(P=0.530)rateofthetwogroups.Mostrelevantpoor-prognosticfactorswereKi-67overexpressionandnegativehormonalreceptors.Cumulativesurvivalwas98.2%vs.86.5%betweenlowKi-67(≤20%)andhighKi-67(>20%).ThehazardratioofpatientswithhighKi-67was16.585[95%confidenceinterval(CI),1.969-139.724;P=0.010].Meanwhile,ER(-)/PR(-)patientswithMIBChadcumulativesurvivalof79.3%comparedwith97.5%forER(+)orPR(+)patientswithMIBC.ThehazardratioforER(-)/PR(-)patientswithMIBCwas19.149(95%CI,3.702-99.057;P<0.001).SubgroupanalysisshowedthatchemotherapycouldimprovetheoutcomesofER(-)/PR(-)patients(P=0.014),butnotthosewhooverexpressKi-67(P=0.105).Conclusions:PatientswithMIBCwhooverexpressKi-67and