Study Comparing Full-dose Radiotherapy Versus Reduced Dose in the Management of Bone Metastasis in Patients With Breast Cancer Receiving Zoledronic Acid

Inclusion Criteria: * Female patients aged ≥ 18 years. * Histologically confirmed diagnosis of breast cancer with at least one bone metastases. * Radiologically documented solitary or multiple osteolytic or osteoblastic lesions in axial skeleton or in the extremities in which radiotherapy is indicated. * Pain and/or analgesic score ≥ 3 (see section 3.5.2) at the bone site to be irradiated. * ECOG performance status ≤ 2. * Life expectancy more than 6 months. Exclusion Criteria: * Patients in whom the target lesion(s) is not detectable by conventional techniques (i.e. X-rays MRI or CT scan). * Presence of pathological fracture in the target lesion(s). * Prior irradiation of the painful area(s) to be irradiated. * Known hypersensitivity to zoledronic acid or other biphosphonates. * Previous treatment with bisphosphonates for the current disease; any treatment with biphosphonates for other indications should anyway have been discontinued at least two years before randomization into the study. * Skeleton-related complications (e.g., pathological fractures, orthopedic intervention to treat or stabilize an osteolytic defect, spinal cord compression) during the last 3 weeks prior to the first infusion of trial medication. * Change in anticancer therapy within the 2 weeks prior to screening assessments and/or test treatment start. * Patients with severe renal function (serum creatinine \> 400 umol/l or \> 4.5 mg/dl or calculated creatinine clearance ≤ 30 ml/minute) or with prior renal transplantation. Creatinine clearance will be calculated using the following formula: Creatinine clearance = (140-age\[yr\])(body weight \[kg\]) x 0.85 (72) (serum creatinine \[mg/dL\]) or Creatinine clearance = (140-age\[yr\])(body weight \[kg\]) x 0.85 (0.814) (serum creatinine \[µmol/L\]) * Corrected (adjusted for serum albumin) serum calcium concentration \< 8.0 mg/dl (2.00 mmol/L). * Patients with clinically symptomatic brain metastases * Bone metabolism disorder, e.g. Paget disease, primary hyperparathyroidism * Serious intercurrent illness other than breast cancer that can interfere with the evaluation of the effect of the therapy. * Pregnancy and lactation. * Women of childbearing potential not on an effective form of contraception. * Known history or present abuse of alcohol or drugs (accepted social alcohol usage will not exclude the patient) * Patients who, in the opinion of the investigator, are unlikely to cooperate fully during the study. Other protocol-defined inclusion/exclusion criteria may apply.