Cyclophosphamide, Paclitaxel, and Trastuzumab in Treating Stage I-II HER2/Neu Positive Breast Cancer After Surgery

Inclusion Criteria: * Histologically confirmed newly diagnosed stage I-II HER2/neu positive breast cancer * Women of reproductive potential must be non-pregnant and non-nursing and must agree to employ an effective barrier method of birth control throughout the study and for up to 6 months following treatment * Women of child-bearing potential must have a negative pregnancy test within 7 days of initiating study (no childbearing potential is defined as age 55 years or older and no menses for two years or any age with surgical removal of the uterus and/or both ovaries) * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Within 30 days prior to enrollment: Absolute neutrophil count greater than or equal to 1,500/mcl * Within 30 days prior to enrollment: Platelet count equal to or greater than 150,000/mcl * Within 30 days prior to enrollment: Hemoglobin \> 11 gm/dl * Within 30 days prior to enrollment: Alkaline phosphatase equal or less than 1.5 times the upper limit of normal (ULN) * Within 30 days prior to enrollment: Total bilirubin equal to or less than 1.5 times the ULN * Within 30 days prior to enrollment: Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) no greater than 1.5 times the ULN * Within 30 days prior to enrollment: Creatinine less than 1.5 times the ULN * Able to give informed consent * All included subjects must have normal cardiac function as defined by an ejection fraction of \> 50% by echocardiogram * Able to return for treatment and follow-up on the specified days Exclusion Criteria: * Prior malignancy; except for adequately treated basal cell or squamous cell skin cancer or noninvasive carcinomas * Subjects with pre-existing grade II peripheral neuropathy * History of previous chemotherapy * Stage IV or metastatic breast cancer * Pregnant or nursing women * Inability to cooperate with treatment protocol * No active serious infections or other conditions precluding chemotherapy * Any comorbidity or condition which, in the opinion of the investigator, may interfere with the assessments and procedures of this protocol e.g. unstable angina, myocardial infarction within 6 months, severe infection, etc. * Known hypersensitivity to any component of required drugs in the study * Known positive for human immunodeficiency virus (HIV) or infectious hepatitis, type A, B or C or active hepatitis * Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from signing the informed consent form * Myocardial infarction within 6 months prior to enrollment or has New York Heart Association (NYHA) class III or IV heart failure uncontrolled angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic evidence of acute ischemia or active conduction system abnormalities; prior to study entry, any electrocardiographic (ECG) abnormality at screening has to be documented by the investigator as not medically relevant