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.