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

DISEASE CHARACTERISTICS:

• Histologically confirmed invasive carcinoma of the breast with 0-3 positive axillary lymph nodes

  • Meets 1 of the following criteria for node-negative disease:

    • Negative sentinel lymph node biopsy
    • At least 6 negative axillary lymph nodes removed and determined to be negative by axillary dissection

  • Meets 1 of the following criteria for node-positive disease (1-3 positive axillary lymph nodes):

    • At least 1 positive lymph node by sentinel lymph node biopsy AND at least 6 axillary lymph nodes removed by axillary dissection; of all the nodes removed from both the sentinel lymph node biopsy and the axillary dissection, 1-3 must be positive
    • At least 6 lymph nodes removed by axillary dissection; 1-3 nodes from the axillary dissection must be positive
• "High-risk" disease that warrants chemotherapy (ultimately determined by the treating physician)

• Modified radical mastectomy or lumpectomy within the past 84 days required

  • Negative tumor margins for invasive cancer and ductal carcinoma in situ (DCIS)
  • Lobular carcinoma in situ (LCIS) at the margin allowed
• Multicentric disease allowed provided margins and axillary nodes are negative after resection
• Bilateral synchronous disease allowed
• Invasive cancer on one side and DCIS or LCIS on the contralateral side is allowed provided all other eligibility criteria are met
• No locally advanced, inflammatory, or metastatic breast cancer
• No dermal lymphatics involvement, even if there are no clinical signs of inflammatory cancer
• HER2/neu positive, negative, or unknown

• Hormone receptor status:

  • Any estrogen and/or progesterone receptor status

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Sex:

• Female

Menopausal status:

• Premenopausal or postmenopausal

Performance status:

• CTC 0-1

Life expectancy:

• Not specified

Hematopoietic:

• Absolute neutrophil count at least 1,000/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin no greater than 1.5 times upper limit of normal

Renal:

• Creatinine no greater than 2.0 mg/dL

Cardiovascular:

• No active congestive heart failure
• No myocardial infarction within the past 6 months

Other:

• Not pregnant or nursing
• Fertile patients must use effective nonhormonal contraception during and for at least 2 months after study participation
• No other malignancy within the past 5 years except curatively treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No prior trastuzumab (Herceptin^®) for this malignancy

Chemotherapy:

• See Disease Characteristics
• No prior chemotherapy for this malignancy
• No other concurrent chemotherapy

Endocrine therapy:

• No prior hormonal therapy for this malignancy except tamoxifen given for up to 4 weeks
• Prior tamoxifen or other selective estrogen receptor modulators (SERMs) for prevention or other indications (e.g., osteoporosis) allowed

• No concurrent exogenous hormonal therapy (including oral contraceptives, postmenopausal hormone replacement therapy, or raloxifene) except:

  • Steroids for adrenal failure
  • Hormonal agents for nondisease-related conditions (e.g., insulin for diabetes or synthroid for hypothyroidism)
  • Intermittent dexamethasone as an antiemetic and premedication for paclitaxel
• No concurrent tamoxifen or other SERMs

Surgery:

• See Disease Characteristics

Other:

• No concurrent dexrazoxane
• No concurrent raloxifene
• Concurrent bisphosphonates for osteoporosis allowed
• Concurrent trastuzumab (Herceptin^®) allowed for patients with HER2-positive disease
• Concurrent enrollment on adjuvant bisphosphonate studies allowed
• Concurrent enrollment on adjuvant hormonal studies allowed provided hormonal therapy does not commence until completion of study chemotherapy