This phase II trial aims to study the efficacy and safety of 12 weeks adjuvant docetaxel plus trastuzumab in patients with tumors ≤1cm, node-negative, HER2-positive breast cancer.

Many clinical trials has showed the superiority of combining trastuzumab to chemotherapy in the treatment of HER2 positive early breast cancer with tumor size ≥1cm or node metastasis.But in pT1n0m0 breast cancer patients, patients with HER2 positive tumor show worse prognosis than those with HER2 negative tumor.A short duration of trastuzumab administration contaminately with chemotherapy may have similar efficacy and lowerer toxiticy compared with standard one year therapy.Our study aims to study the efficacy and safety of 12 weeks adjuvant docetaxel plus trastuzumab in patients with tumors ≤1cm, node-negative, HER2-positive breast cancer.

Inclusion Criteria:

Women aged ≥18 years

Have finished radical operation

Pathologically confirmed dignosis of infiltrating primary breast cancer

According to AJCC ,pT≤1cm, pN0,no evidence for metastasis

Operation specimens are available for ER, progesterone receptor (PR) and Her2 detection, patients should be Her2 positive tumor (3+ by IHC or FISH+ )

Has Eastern Cooperative Oncology Group (ECOG) Performance Score 0-1,expected survival time > 12 months

Adequate bone marrow function,adequate liver and renal function,and adequate coagulation function.

Women with potential child-bearing must have a negative pregnancy test (urine or serum) within 7 days of drug administration and agree to use an acceptable and effective method of contraception to avoid pregnancy during the study.

Written informed consent according to the local ethics committee requirements.

Exclusion Criteria:

pT>1cm or node positive

Metastatic breast cancer

Any prior systemic or loco-regional treatment of breast cancer, including chemotherapy in 28 days

With a history of malignant tumor except uterine cervix cancer in situ or skin basal cell carcinoma

Patients with medical conditions that indicate intolerant to adjuvant chemotherapy and related treatment, including severe infection, coagulation disorder,active peptic ulcer, coagulation disorder, connective tissue disease or myelo-suppressive disease

Has symptomatic peripheral neuropathy > grade 2 according to NCI

Known severe allergy to any drugs in this study

Has cadiac Dysfunction or lung dysfunction defined as follows:

1. grade ≥3 CHF according to NCI CTCAE v 4.0 or NYHA≥II
2. angina which requires drug control ,cardiac infraction,and any other vascular disease with apparent clinical symptoms
3. uncontrolled high-risk arryhthmia
4. unconrolled hypertension

Has active hepatitis B or hepatitis C with abnormal liver function tests (LFTs) or is known to be HIV positive

Patient is pregnant or breast feeding

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