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.