RATIONALE: Colony-stimulating factors, such as filgrastim or pegfilgrastim, may increase the number of immune cells found in bone marrow or peripheral blood and may help a person's immune system recover from the side effects of chemotherapy. It is not yet known whether filgrastim or pegfilgrastim is more effective than standard treatment in preventing neutropenia in women who are receiving adjuvant chemotherapy for breast cancer.

PURPOSE: Randomized phase IV trial to compare the effectiveness of filgrastim or pegfilgrastim with that of standard treatment in preventing neutropenia in women who are receiving chemotherapy after undergoing surgery for breast cancer.

OBJECTIVES:

• Determine the efficacy of filgrastim (G-CSF) or pegfilgrastim as secondary prophylaxis versus standard management after the first neutropenic event in maintaining dose-intensity of adjuvant chemotherapy in patients with early breast cancer.
• Determine the proportion of patients who experience at least one neutropenic event.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to age (60 and under vs over 60) and participating center.

Patients receive chemotherapy as per local practice. After the first neutropenic event, patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients receive filgrastim (G-CSF) subcutaneously (SC) for 7 days beginning 2 days after the final dose in a course of adjuvant chemotherapy (e.g., beginning on day 3 for a course of chemotherapy administered on day 1 only OR beginning on day 10 for a course of chemotherapy administered on days 1 and 8) OR a single dose of pegfilgrastim SC administered approximately 24 hours after chemotherapy that is administered on day 1 only.
• Arm II: Patients receive standard conservative management. Patients are followed for up to 10 years.

PROJECTED ACCRUAL: A total of 400 patients will be accrued for this study within 7 years.

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)