Safety and Efficacy of Zoledronic Acid in Patients With Breast Cancer With Metastatic Bone Lesions

The SMR was computed by summing all Skeletal Related Event(s) (SREs)which occurred during the observation period and dividing it by the ratio "days of observation period / 365.25", for each participant. SRE was defined as: pathologic bone fracture, spinal cord compression, surgery to bone both curative and prophylactic, radiation therapy to bone, or hypercalcemia of malignancy.

SMR (years) = 365.25 x SMR(days) where SMR (days) = total number of SREs / total SRE risk period (days). Risk period for SMR was computed as the days from randomization date to the date of last visit.

Skeletal Related Events (SREs) are defined as a:

• pathologic bone fracture such as non-vertebral and vertebral compression fractures
• spinal cord compression identified by positive diagnosis documented by X-ray evidence
• surgery to bone both curative and prophylactic
• radiation therapy to bone including palliative, therapeutic or prophylactic
• hypercalcemia of malignancy, defined as a corrected serum calcium > 12 mg/dl (3.00 mmol/l) or a lower level of hypercalcemia which is symptomatic and which requires active treatment other than rehydration.

Skeletal Related Events (SREs) are defined as a:

• pathologic bone fracture such as non-vertebral and vertebral
• spinal cord compression identified by X-rays evidence
• surgery to bone both curative and prophylactic
• radiation therapy to bone including palliative, therapeutic or prophylactic
• hypercalcemia of malignancy, defined as a corrected serum calcium > 12 mg/dl (3.00 mmol/l) or a lower level of hypercalcemia which is symptomatic and which requires active treatment other than rehydration. Annual incidence for each SRE was computed in the same way as annual overall SMR.

Median Time to first skeletal related event (SRE) is defined as the time from randomization to the date of first occurrence of any SRE which includes at least one of the following: radiation therapy to bone, pathologic bone fracture, spinal cord compression, surgery to bone, and hypercalcemia of malignancy (HCM). Due to the few numbers of SRE, Kaplan-Meier estimate never reaches a failure probability >=25%; so median time, 25th and 75th percentiles are not determined.For this reason only the estimated percentage of patient SRE free are reported at each time point.

Percentage of participants SRE free is defined as the Kaplan-Meier estimate of participants free of any Skeletal Related Events(SRE) at each time point.

Skeletal Related Events (SREs) are:

• pathologic bone fracture; non-vertebral and vertebral
• spinal cord compression identified by X-rays
• surgery to bone both curative and prophylactic
• radiation therapy to bone (palliative, therapeutic or prophylactic)
• hypercalcemia of malignancy, defined as a corrected serum calcium > 12 mg/dl (3.00 mmol/l) or a lower level which is symptomatic and requires treatment other than rehydration.

Bone pain was assessed by means of a pain score obtained using the Brief Pain Inventory (BPI) questionnaire. The BPI can produce three pain scores: worst pain, a composite pain score, and a pain interference score. The composite pain score, which is the average of questions 3, 4, 5 and 6 of the questionnaire was used in this study. Pain was rated on a scale of 0 (no pain) to 10 (pain as bad as you can imagine). The outcome is given as the median score for participants at baseline, and 3, 6, 9 and 12 months of treatment

Pain intensity at rest and on movement is rated by the patient by means of a validated 6-point Verbal Rating Scale (VRS) and refers to the pain which occurred during the last week before the assessment. Median score value is the median of all the observed scores (none=0, very mild=1, mild=2, moderate=3, severe=5 and very severe=6) at each time point.

The analgesic score used for this study is modified from the Radiation Therapy Oncology Group (RTOG) analgesic score scale. The scale represents type of medication administered from 0 to 4 where:

0 = None

• = Minor analgesics (aspirin, NSAID, acetaminophen, propoxyphene, etc.)
• = Tranquilisers, antidepressants, muscle relaxants, and steroids
• = Mild narcotics (oxycodone, meperidine, codeine, etc.)
• = Strong narcotics (morphine, hydromorphone, etc.) The outcome is given a the median score for the participants at Baseline and 3, 6, 9 and 12 months of treatment

ECOG Performance Score has 4 grades. 0 = Fully active, able to carry out all pre-disease activities; 1 = Restricted in strenuous activity but ambulatory and able to carry out work of light or sedentary nature; 2 = Ambulatory and capable of all self-care but unable to carry out work activities. Active about 50% of waking hours; 3 = Capable of limited self-care, confined to bed/chair more than 50% of waking hours; 4 = Completely disabled; cannot carry on self-care. Totally confined to bed/chair. Outcome is given as median score for participants at Baseline and 3, 6 , 9 and 12 months of treatment