Objective  The aim of this study is to analyze the clinicopathological features and survival for patients with a tumor size ≤1 cm, and to clarify the prognostic significance of triple-negative breast cancer (TNBC).

  Methods  Data from 312 patients with operable primary breast cancer with tumor size ≤1 cm, who were admitted to the Tianjin Medical University Cancer Institute and Hospital from January 2002 to June 2005, were gathered and analyzed, and the clinicopathological features, recurrence, metastasis, and survival status between TNBC and non-TNBC patients were compared. SPSS17.0 software was used for statistical analysis, with statistical significance considered at P < 0.05.

  Results  The rates of 5-year disease-free survival (DFS) and breast cancer-specific survival (BCSS) of the TNBC patients were 81.4% and 84.7%, respectively, lower than those of the non-TNBC patients (P = 0.038; P = 0.047). In the lymph node-negative patients, the rates of 5-year DFS and BCSS of the TNBC patients were 82.8% and 85.0%, respectively, lower than those of the non-TNBC patients (P = 0.033; P = 0.019). In the multivariate Cox regression hazard analysis, lymph node infiltration was associated with a higher hazard ratio (HR) for disease recurrence (HR: 3.721, 95% CI: 1.743-7.941, P = 0.001), and BCSS (HR: 3.560, 95% CI: 1.521-8.330, P = 0.003). The TNBC group was associated with a higher HR for tumor recurrence (HR: 2.208, 95% CI: 1.028-4.742, P = 0.042) compared with the non-TNBC group.

  Conclusion  Lymph node status and TNBC are independent prognostic factors for the recurrence and metastasis of tumor, while lymph node infiltration is the single independent prognostic factor for BCSS. TNBC can be an independent risk factor for T1a and T1b node-negative invasive breast cancer.