Forty patients with skeletal metastasis who were scheduled to undergo local radiotherapy were included in this study. The purpose of the study was to determine the effect of zoledronate, a bisphosphonate, in collagen breakdown and bone loss secondary to radiation therapy. Patients were randomized to receive the first dose of the zoledronate either before, or after radiotherapy treatment. Findings indicated a significant reduction in lysylpyridinoline (LP) excretion and a reduction in hydroxylysylpyridinoline (HP) excretion when the bisphosphonate was administered prior to the therapy.