Tumoricidal effect and pain relief after concurrent therapy by strontium-89 chloride and zoledronic acid for bone metastases.

OBJECTIVE: The purpose of this study was to investigate the palliative and tumoricidal effects of concurrent therapy of strontium-89 chloride (89SrCl2) and zoledronic acid (ZA) for painful bone metastases. SUBJECTS AND METHODS: Fifty-one patients with painful bone metastases prostate cancer (n=17), lung cancer (n=13), breast cancer (n=12), other cancers (n=9) were treated. Bone metastases was confirmed in all patients by technetium-99m hydroxymethylene diphosphonate (99mTc-HMDP) bone scintigraphy. The numeric rating scale (NRS) and performance status (PS) were used to assess the degree of pain and patients' physical condition. The extent of bone metastases was assessed with imaging modalities including CT, MRI and/or 99mTc bone scintigraphy before treatment and 2 or 3 months after. RESULTS: The pain relief response of 89SrCl2 with ZA for bone metastases was 94% (48/51) from 1 to 3 months after treatment. The tumoricidal effect of concurrent therapy by 89SrCl2 with ZA for painful bone metastases was 8/22 as shown by imaging modalities and the rate of non-progressive disease (non-PD) was 19/22. Pain due to bone metastases assessed with the NRS was significantly improved (P<0.001) in many types of primary cancer, including prostate, breast and lung cancers. CONCLUSION: Concurrent therapy of 89SrCl2 with ZA may offer not only pain relief, but also a tumoricidal effect for painful bone metastases.