Efficacy and Safety of Adjuvant Docetaxel and Trastuzumab in Stage I HER2-positive Breast Cancer

Inclusion Criteria:

1. Female aged 18 - 70 years old;
2. The histopathological confirm of invasive breast cancer;
3. HER-2 positive: immuno-histochemistry (IHC) 3+ or fluorescence in situ hybridization (FISH) confirmed amplification of erbb2 gene;
4. Tumor must be ≤ 2cm in greatest dimension, negative axillary lymph node or with micrometastasis (axillary nodes with tumor clusters ≤ 0.2cm);
5. No more than 90 days from the patient's most recent breast surgery for this breast cancer;
6. Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1;
7. Adequate bone marrow function: neutrophil ≥ 1500/mm\^3, hemoglobin ≥ 9 g/dl, and platelets ≥ 100,000/mm\^3;
8. Adequate liver and renal function: creatinine ≤ 1.5 folds of the upper limit of normal value; aspartate aminotransferase and alanine aminotransferase ≤ 1.5 folds of the upper limit of normal value, aspartate aminotransferase and alanine aminotransferase ≤ 2 folds of the upper limit of normal value for patient with Gilbert 's syndrome;
9. Left ventricular ejection fraction (LVEF) ≥ 50%;
10. Willing and able to sign informed consent.

Exclusion Criteria:

1. Any of the following due to teratogenic potential of chemotherapy: pregnant women, nursing women, women of childbearing potential who are unwilling to employ adequate contraception;
2. Locally advanced tumors at diagnosis, including tumors fixed to the chest wall, peau d'orange, skin ulcerations/nodules, or clinical inflammatory changes;
3. History of prior chemotherapy in the past 5 years;
4. History of prior trastuzumab therapy;
5. Patients with a history of previous invasive breast cancer;
6. Active, unresolved infection;
7. Prior history of any other malignancy in the past 5 years, except for early stage tumors of the skin or cervix treated with curative intent;
8. Can not tolerate or be allergic to chemotherapy, anti-HER-2 therapy or pharmaceutical materials such as benzyl alcohol;
9. ≥ grade 2 neuropathy;
10. Active cardiac disease: Any prior myocardial infarction (asymptomatic changes on EKG suggestive of old myocardial infarction is not an exclusion); Documented congestive heart failure (CHF); Current use of any therapy specifically for CHF; Current uncontrolled hypertension (diastolic \>100 mmHg or systolic \> 200 mmHg); Clinically significant pericardial effusion;
11. The antibody of hepatitis C virus, HIV or Treponema pallidum positive; HBsAg positive and hepatitis B virus DNA in peripheral blood ≥ 10\^3 copy/mL；
12. Enrollment on other Investigational studies within 30 days;
13. Not allowed by the investigators.