RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die.

PURPOSE: Phase II trial to study the effectiveness of vinorelbine in treating older women who have stage IV breast cancer.

OBJECTIVES:

• Determine the objective response rate in elderly women with stage IV breast cancer treated with oral vinorelbine.
• Determine the toxicity profile of this drug in these patients.
• Determine the time to progression in patients treated with this drug.
• Determine the quality of life of patients treated with this drug.
• Assess individual variation in responses (toxicity and/or activity), pharmacokinetic parameters, and/or biologic correlates due to genetic differences in enzymes involved in the transport, metabolism, and/or mechanism of action of this drug in these patients.

OUTLINE: Patients receive oral vinorelbine once weekly. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.

Quality of life is assessed at baseline and then after completion of the second course.

Patients are followed every 3 months for 5 years.

DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed stage IV breast cancer

• Eligible to receive first- or second-line chemotherapy

• At least 1 unidimensionally measurable lesion

  • At least 20 mm in longest diameter
  • Must be completely outside prior irradiation port unless there is proof of progressive disease after completion of prior radiotherapy

• No untreated brain metastases

  • Current metastatic CNS disease allowed only if previously treated and clinically stable at study entry

• No meningeal carcinomatosis

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age:

• 65 and over

Sex:

• Female

Menopausal status:

• Not specified

Performance status:

• ECOG 0-2

Life expectancy:

• At least 12 weeks

Hematopoietic:

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Total bilirubin no greater than 1.5 times upper limit of normal (ULN) OR
• Direct bilirubin normal if total bilirubin elevated or less than 2.5 times ULN because of Gilbert's syndrome

Renal:

• Creatinine no greater than 2 times ULN

Other:

• No grade 2 or greater peripheral neuropathy
• No other significant medical condition that would preclude study
• No active infection within the past 2 weeks
• No dysphagia or inability to swallow intact capsules

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• See Disease Characteristics
• No more than 1 prior chemotherapy regimen for metastatic disease
• No prior vinca alkaloids
• At least 4 weeks since other prior chemotherapy and recovered

Endocrine therapy:

• Prior hormonal therapy allowed
• No concurrent hormonal therapy

Radiotherapy:

• See Disease Characteristics
• No prior radiotherapy to 25% or more of bone marrow
• At least 3 weeks since prior radiotherapy and recovered

Surgery:

• At least 3 weeks since prior major surgery