ObjectiveTo compare clinicopathologic characteristics and prognosis between HER2-low and HER2-negative with stage T1 and T2 triple-negative breast cancer (TNBC). MethodsThe patients with stage T1 and T2 TNBC treated at the Affiliated Hospital of Southwest Medical University from June 2019 to June 2021 were retrospectively collected. The clinicopathologic features were analyzed using two-sided Chi-square test. Multivariate binary logistic regression identified risk factors for 3-year postoperative recurrence/metastasis. Kaplan-Meier survival curves was used to compare 3-year disease-free survival (DFS) between the patients with HER2-low and HER2-negative. The statistical significance was defined as α=0.05. ResultsA total of 126 patients with stage T1 and T2 TNBC were enrolled, 63 were HER2-negative and 63 HER2-low. Compared with HER2-negative patients, HER2-low patients demonstrated significantly higher proportions of: Age ≥50 years old, postmenopausal status, lymphovascular invasion (P<0.05). HER2 expression level and axillary lymph node metastasis were the independent risk factors for 3-year postoperative recurrence/metastasis in the patients with stage T1 and T2 TNBC (P<0.05). The patients with HER2-low expressing demonstrated significantly inferior 3-year DFS compared to patients with HER2-negative (χ2=7.741, P=0.005). ConclusionsFindings of this study suggest that among patients with stage T1 and T2 TNBC, HER2-low expression is associated with advanced age (≥50 years), menopausal status, and lymphovascular invasion. It may serve as an indicator of a distinct biologic subgroup or unfavorable pathologic characteristics. Patients with stage T1 and T2 TNBC who have HER2-low expression and positive lymph node metastasis require close monitoring for recurrence/metastasis within 3 years postoperatively.