Combined therapy of Sr-89 and zoledronic acid in patients with painful bone metastases

Purpose We evaluated the pain response and daily discomfort in patients with painful bone metastases treated by merging 89Sr-chloride and zoledronic acid. The results were compared with those of patients who received 89Sr-chloride or zoledronic acid separately. Methods 25 patients (12 women; mean age 65 ± 13 years) chronically treated with zoledronic acid underwent bone pain palliation with 150 MBq of 89Sr-chloride at least 6 months later that bisphoshonate therapy started (group A). 13 patients (6 women; mean age 70 ± 12 years) received 89Sr-chloride alone (group B) and 11 patients (5 women; mean age 69 ± 12 years) were chronically treated and continued to receive only zoledronic acid therapy (group C), both constituted the control groups. Patients kept a daily pain diary assessing both their discomfort and the pain of specific sites by using a visual analog scale (VAS), rating from 0 (no discomfort–no pain) to 10 (worst discomfort–pain). These diaries were reviewed weekly for 2 months and three different physicians rated the pain response on a scale of −2 (considerable deterioration) to +2 (considerable improvement). Results Baseline characteristics were similar in the three groups. The reduction of total discomfort and of bone pain in the group A was significantly greater as compared to group B (P < 0.01) and group C (P < 0.01). During the monitored period, a significant improvement of clinical conditions was observed in the group A, varying the rate from −1 to 1 as compared to both groups B and C in which the rate changed from −1 to 0. Conclusion Our findings indicate that combined therapy of 89Sr-chloride and zoledronic acid in patients with painful bone metastases is more effective in treating pain and improving clinical conditions than 89Sr-chloride or zoledronic acid used separately.