Four Versus Six Cycles of Cyclophosphamide/Doxorubicin or Paclitaxel in Adjuvant Breast Cancer

Eligibility Criteria:

• Patients must have histologically confirmed invasive carcinoma of the female breast, with 0-3 positive axillary lymph nodes
• Patients must have 0-3 positive axillary lymph nodes to be eligible for this study; patients with node-negative breast cancer should have sufficiently "high risk" disease to warrant chemotherapy; as general guidelines, node-negative patients with tumors of >= 1 cm or estrogen or progesterone receptor negative tumors of any size may be eligible; ultimately though, the definition of "high risk" may be determined by the treating physician, and if the treating physician feels the patient warrants chemotherapy, the patient is eligible; for patients with 1-3 positive axillary nodes, the patient is eligible regardless of primary breast tumor characteristics, if in the opinion of the treating physician, chemotherapy is deemed potentially beneficial to the patient
• If the patient has had a negative sentinel node biopsy, then no further axillary dissection is required, and the patient is determined to be node-negative; if an axillary dissection, without a sentinel node biopsy, is performed to determine nodal status, at least six axillary lymph nodes must be removed and analyzed and negative for the patient to be considered node-negative; axillary nodes with single cells or tumor clusters = 0.2 mm will be considered positive
• If the patient has a sentinel node biopsy and one of the sentinel nodes is positive, as defined by tumor clusters > 0.2 mm, an axillary dissection must be performed; a total of at least 6 axillary lymph nodes, including sentinel nodes plus the subsequent dissection, must be removed for the patient to be eligible; of all the lymph nodes removed from both the sentinel node procedure and the axillary dissection, 1-3 must be positive for the patient to be eligible as a node-positive patient; if an axillary dissection is done without a sentinel node procedure, at least 6 lymph nodes must be removed and a 1-3 nodes must be positive for the patient to be considered node-positive and eligible for this study
• Determination of involvement of axillary nodes with metastatic cancer will follow the revised tumor-node-metastasis (TNM) staging system: axillary nodes with single cells with tumor clusters = 0.2 mm will be considered to be positive
• Patients with estrogen-receptor and/or progesterone receptor negative, positive, or unknown tumors are eligible; estrogen-receptor (ER) and progesterone receptor (PgR) assays should be performed by immunohistochemical methods according to the local institution's standard protocol
• Patients with human epidermal growth factor receptor 2 (HER2) positive, negative or unknown disease are eligible for this trial; patients whose tumors are HER2 positive by either immunohistochemistry 3+ staining or demonstrate gene amplification by fluorescence in situ hybridization (FISH) may receive trastuzumab
• There must be negative tumor margins for invasive cancer and ductal carcinoma in situ (DCIS) in the case of mastectomy or lumpectomy; lobular carcinoma in situ (LCIS) is acceptable at the margin
• Patients with multi-centric breast cancer are eligible as long as all known disease is resected with negative margins, and have 0-3 positive axillary lymph nodes
• Patients must be registered within 84 days of the last breast surgery; patients must have undergone either modified radical mastectomy or lumpectomy; for patients undergoing sentinel node sampling or axillary dissection a simple mastectomy is acceptable; lumpectomy patients must receive radiation therapy; for patients treated with radiation therapy prior to chemotherapy, the patients should be registered on this study after the conclusion of radiation, with chemotherapy administration beginning within 7 days of registration
• All primary breast and axillary node surgery must be completed prior to enrollment on study
• No previous trastuzumab, chemotherapy or hormonal therapy for this malignancy