Statement: WOCBP that refuse to use contraception are excluded from the primary trial, but may be eligible for the secondary trial.
Primary_evidence: Inclusion Criteria:   Non-metastatic primary invasive breast cancer overexpressing HER2 (determined by immunohistochemistry 3+ or positive fluorescence in situ hybridization test) that has been histologically confirmed, adequately excised, axillary node positive or negative, and tumor size at least T1c according to Tumor/Node/Metastasis (TNM) staging   Completion of at least 4 cycles of (neo-)adjuvant systemic chemotherapy, definitive surgery, and radiotherapy, if applicable   Known hormone receptor status   Baseline left ventricular ejection fraction (LVEF) greater than or equal to (  ) 55 percent (%) Exclusion Criteria:   Prior invasive breast carcinoma   Other malignancies except for curatively treated basal and squamous cell carcinoma of the skin or in situ carcinoma of the cervix   Clinical T4 tumors   Cumulative doxorubicin exposure greater than (>) 360 milligrams per meter-squared (mg/m^2) or epirubicin >720 mg/m^2 or any prior anthracyclines unrelated to the present breast cancer   Peripheral stem cell or bone marrow stem cell support   Prior mediastinal irradiation except for internal mammary node irradiation for the present breast cancer   Non-irradiated internal mammary nodes or supraclavicular lymph node involvement   Prior anti-HER2 therapy for any other reason or other prior biologic or immunotherapy for breast cancer   Concurrent anti-cancer treatment in another investigational trial   Serious cardiac or pulmonary conditions/illness, or any other conditions that could interfere with planned treatment   Poor hematologic, hepatic, or renal function   Pregnancy or lactation   Women of childbearing potential or less than 1 year post-menopause unwilling to use adequate contraceptive measures
Secondary_evidence: INCLUSION CRITERIA (Disease Characteristics):   Diagnosis of breast cancer   Stage I or II disease   No more than 10 positive lymph nodes   First-time diagnosis   Under the age of 50 at diagnosis   Finished active treatment within the past 2 months   English-speaking only   Must live within 30 miles of Magee Women's Hospital, Pittsburgh, Pennsylvania   INCLUSION CRITERIA (Patient Characteristics):   Female patients only   Must be able to communicate   EXCLUSION CRITERIA (Patient Characteristics):   Other prior malignancies except skin cancer   PRIOR CONCURRENT THERAPY:   See Disease Characteristics