DISEASE CHARACTERISTICS:

• Histologically confirmed invasive breast cancer

  • No locally advanced or metastatic breast cancer, including supraclavicular fossa metastases

• Prior neutropenic event on current chemotherapy regimen, defined as 1 of the following:

  • Hospitalization due to neutropenia
  • Absolute neutrophil count ≤ 1.5 times upper limit of normal and considered sufficiently low to require a treatment delay or a dose reduction > 15% of planned dose

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Sex:

• Female

Menopausal status:

• Not specified

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• See Disease Characteristics

Hepatic:

• Not specified

Renal:

• Not specified

Other:

• No other concurrent malignancy
• Considered suitable risk and fitness status to continue adjuvant chemotherapy

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No prior filgrastim (G-CSF) or pegfilgrastim

Chemotherapy:

• See Disease Characteristics
• No prior chemotherapy other than current regimen

Endocrine therapy:

• Prior tamoxifen allowed

Radiotherapy:

• Concurrent radiotherapy allowed
• No concurrent sandwich/synchronous radiotherapy (i.e., administered during a break in the chemotherapy regimen)

Surgery:

• See Disease Characteristics

Other:

• Concurrent enrollment on other licensed chemotherapy trials allowed provided G-CSF is not excluded (e.g., TACT or TANGO trials)
• Concurrent enrollment in the sequential arm of the SECRAB trial allowed (synchronous arm ineligible)