DISEASE CHARACTERISTICS:

• Histological diagnosis of invasive breast carcinoma

  • Cytological proof of malignancy alone is not sufficient
  • Early stage disease (T0-3, N0-2, M0) without clinical suspicion or evidence of distant metastases on routine staging
  • No locally advanced breast cancer (T4 and/or N3 disease)

• Completely resected disease by breast-conserving surgery with axillary node clearance or modified radical mastectomy within the past 4-8 weeks

  • Negative surgical margins required, unless either of the following are true:

    • Deep surgical margins after full thickness resection
    • Noninvasive cancer at surgical margins for which a mastectomy is planned after completion of study chemotherapy
  • No contraindication for or refusal of postoperative radiotherapy in patients who underwent prior breast-conserving surgery
• Definite indication for adjuvant chemotherapy

• No prior or current invasive breast cancer or bilateral breast cancer

  • Prior surgically-treated ductal carcinoma in situ or lobular carcinoma in situ allowed

• Hormone receptor status:

  • Estrogen receptor- and/or progesterone receptor-positive or -negative tumor

PATIENT CHARACTERISTICS:

• Sex: male or female
• Menopausal status: premenopausal or postmenopausal
• No previous malignancy except basal cell carcinoma, carcinoma in situ of the cervix, or any cancer from which the patient has been disease-free for 10 years and for which treatment consisted solely of resection
• ECOG status 0 or 1
• Hemoglobin > 9 g/dL
• WBC > 3,000/mm³
• Platelet count > 10,000/mm³
• Bilirubin normal (unless due to known Gilbert's disease)
• AST and ALT ≤ 1.5 times upper limit of normal (ULN)
• Albumin normal
• Creatinine ≤ 1.5 times ULN
• Creatinine clearance > 50 mL/min
• No active, uncontrolled infection
• Not pregnant or nursing
• Fertile patients must use effective contraception
• No concurrent medical, psychiatric, or geographic problems that might prevent completion of treatment or follow-up
• Available for a minimum of 5 years' follow-up
• No known serious viral infection such as active hepatitis B, hepatitis C, or HIV
• No significant cardiac disease, such as impaired left ventricular function or active angina requiring regular anti-anginal medication and/or resulting in restricted physical activity
• No history of significant renal impairment or disease

PRIOR CONCURRENT THERAPY:

• No simultaneous participation in the active intervention phase of another treatment trial
• Not being approached or recruited for another trial within 2 months of study entry

• No previous chemotherapy, hormonal therapy or radiotherapy for the treatment of pre-invasive or invasive cancer except for either of the following:

  • Previous radiotherapy for basal cell carcinoma
  • Previous preoperative endocrine therapy, provided there was no evidence of progression during this therapy, it lasted for less than 6 weeks in duration, and it was stopped at least one month prior to trial entry
• Concurrent luteinizing hormone-releasing hormone analog therapy allowed for premenopausal patients
• More than 4 weeks since prior hormone replacement therapy (HRT) or pre-operative endocrine therapy
• No prior breast conserving surgery if there is a contradiction for or refusal of postoperative radiotherapy