Carboplatin or Docetaxel in Treating Women With Metastatic Genetic Breast Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed breast cancer * BRCA1 or BRCA2 mutation carrier * Metastatic disease * Measurable disease, defined as ≥ 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT scan * Stable, treated brain metastases allowed provided other sites of measurable disease are present * Patients with bone metastases who are currently receiving bisphosphonates for palliation are eligible provided other sites of measurable disease are present * Patients who have not received anthracycline-based chemotherapy in the adjuvant setting may receive a non-taxane, anthracycline regimen as the first-line metastatic treatment and enter the trial at confirmed progression (second-line) * No bone-limited disease * No disease suitable for endocrine therapy alone * Hormone receptor status not specified PATIENT CHARACTERISTICS: * Menopausal status not specified * Sex: female * WHO performance status 0-2 * Life expectancy ≥ 3 months * AST and/or ALT ≤ 5 times upper limit of normal (ULN) (≤ 3 if alkaline phosphatase \> 5 times ULN) * Glomerular filtration rate ≥ 30 mL/min * Normal urea and creatinine * Normal hematological and biochemical studies * Normal bilirubin * Not pregnant or nursing * Fertile patients must use effective contraception during and for 6 months after completion of study treatment * Negative pregnancy test * No known allergy to platinum compounds or mannitol * No known sensitivity to taxanes * No oth…