Comparison of Two Schedules of Zoledronic Acid in Treating Patients With Breast Cancer That Has Spread to the Bone

DISEASE CHARACTERISTICS: * Histologically confirmed primary breast cancer * Advanced disease * Radiographic confirmation of bone metastases (≥ 1 bone scan lesion must be confirmed as metastatic by plain radiographs or CT scan/MRI) * Must have received zoledronic acid to treat metastatic bone disease (i.e., ≥ 4 or 5 zoledronic acid treatments prior to study entry for patients receiving 4- or 3-weekly infusions, respectively) for ≥ 4 months prior to study entry * Any bisphosphonate to treat metastatic bone disease allowed provided it was not given for more than 12 months prior to study entry * No metabolic bone disease (e.g., Paget's disease of bone) * Osteoporosis allowed * No brain metastases * Hormone receptor status not specified PATIENT CHARACTERISTICS: * Male or female * Menopausal status not specified * WHO or ECOG performance status 0-2 * Life expectancy ≥ 6 months * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * AST and ALT ≤ 3 times upper limit of normal (ULN) * Bilirubin ≤ 1.5 times ULN * Creatinine clearance ≥ 30 mL/min * No poor venous access * No concurrent active dental problems, including infection of the teeth or jawbone (maxilla or mandibular) * No prior or current diagnosis of osteonecrosis of the jaw * No other cancer within the past 5 years except nonmelanomatous skin cancer, carcinoma in situ of the uterine cervix, or superficial bladder cancer treated with curative intent PRIOR CONCUR…