Concurrent use of strontium-89 with external beam radiotherapy for multiple bone metastases: early experience

Objective The aim of the present study was to consider the safety and efficacy of concurrent use of strontium-89 (Sr-89) with external beam radiotherapy (EBRT) for multiple bone metastases, including lesions that require urgent therapy. Methods A retrospective review was performed of a consecutive series of patients who received Sr-89 for multiple bone metastases. Forty-five patients with multiple bone metastases received Sr-89 injection. Since 17 of the 45 patients had osteolytic bone lesions requiring emergent EBRT, they underwent concurrent use of Sr-89 with EBRT (concurrent group). The remaining 28 patients, none of whom had osteolytic lesions requiring urgent EBRT, were given Sr-89 injection only (singularity group). The injection of Sr-89 was to be given during EBRT, or on the day before the first day of EBRT. The dose of EBRT was 30 Gy in 10 fractions or 40 Gy in 20 fractions. Adverse events were evaluated according to hematological toxicity as measured by the Common Terminology Criteria for Adverse Events (V4.0). To assess efficacy, we checked changes in the pain scale and analgesic drug dosages, and the presence or absence of serious complications from bone metastases. Results Fifteen of 17 patients (88.2 %) in the concurrent group and 17 of 28 patients (60.7 %) in the singularity group reported bone pain relief. A statistically significant difference was found between the two groups, and severe complications (spinal cord compression and pathological fracture) from bone metastases could be prevented in all patients in the concurrent group. Severe hematological toxicity (grade 3 or higher) was not observed in the two groups. There was no statistical difference between the two groups. No one required additional intervention. The adverse events were tolerable. Conclusions The results of our study suggest that concurrent use of Sr-89 with EBRT for multiple bone metastases can be performed safely if it is carried out with care, and that it may be an effective therapy in cases requiring emergency treatment.