Oral Vinorelbine or Capecitabine Combined With Trastuzumab as Adjuvant Treatment for Patients With Lymph Node Negative, HER-2 Positive and Small Tumor Size Breast Cancer (ORCHID)

Inclusion criteria

• . women aged 18-70 years old;
• . T ≤1cm and negative lymph node confirmed by histopathology after early breast cancer surgery
• . HER2 positive confirmed by histopathology after early breast cancer surgery（HER2-positive breast cancer defined as a positive in situ hybridization test or an Immunohistochemistry (IHC) status of 3+. If IHC is 2+, a negative in situ hybridization (Fluorescence in situ hybridization (FISH), Chromogenic in situ hybridization (CISH) , or Silver in situ hybridization (SISH)) test is required by local laboratory testing.)
• . Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1;
• . Has adequate organ function meeting the following criteria: (1) adequate bone marrow function: hemoglobin ≥ 90 g/L (no blood transfusion within 14 days); absolute neutrophil count ≥ 1.5 x 109 /L; platelet count ≥ 100 \* 109 /L; (2)adequate liver and kidney function: Alanine Aminotransferase (ALT) ≤ 3×upper limit of normal (ULN), Aspartate Aminotransferase (AST) ≤ 3×ULN, Total Bilirubin (TBIL)≤ 1.5×ULN, serum creatinine ≤ 1×ULN，and with endogenous creatinine clearance rate of \>50 ml/min (Cockcroft-Gault formula).