Abstract： Background:The results of the Trial Assigning IndividuaLized Options for Treatment (TAILORx) suggested that approximately 70％ of T1-2N0M0,hormone receptor-positive,human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients can avoid chemotherapy and receive only adjuvant endocrine therapy.We conducted a retrospective analysis of the clinicopathologic features and prognostic factors of patients with breast cancer who met the inclusion criteria of the TAILORx trial.Methods:According to the enrollment criteria of the TAILORx trial,a retrospective analysis was performed on patients with breast cancer who were treated from January 2008 to December 2015 at Peking University First Hospital.The clinicopathologic characteristics of all patients were analyzed,and prognoses were calculated using the Kaplan-Meier method and a Cox proportionate hazards model.Results:A total of 2430 patients with early stage breast cancer who were admitted at our hospital had complete clinicopathologic data and follow-up information.Of these patients,722 met the inclusion criteria and were enrolled in the present study,accounting for 29.7％ of all patients.Among them,417 (57.8％) patients received only adjuvant endocrine therapy (the non-chemo group),and 305 (42.2％) patients received adjuvant chemotherapy followed by adjuvant endocrine therapy (the chemo group).No statistically significant difference was observed in overall survival (OS) between the two groups (non-chemo vs.chemo:5-year OS:97.9％ vs.97.9％,x2=1.00,P =0.995;hazard ratio [HR] =1.00,95％ confidence interval [CI]:0.46-2.21).A significant difference was observed in disease-free survival (DFS) between the two groups (non-chemo vs.chemo:5-year DFS:97.9％ vs.94.7％,x2 =8.65,P =0.003;HR =3.05,95％ CI:1.40-6.67).The choice of adjuvant therapy was associated with clinicopathologic factors,such as the age at diagnosis,T stage,histologic grade,the Ki67 index,the presence of intravascular tumor thrombus (P ＜ 0.001),pathologic type,and menstrual status (P =0.014).Conclusions:In the absence of internationally recognized multigene testing methods,for patients with early hormone receptorpositive,HER2-negative breast cancer,clinicians can develop a treatment plan based on clinicopathologic features only,which can effectively screen some patients who do not need adjuvant chemotherapy.However,nearly half of patients still receive adjuvant chemotherapy,and whether these patients can be exempted from chemotherapy warrants further exploration.