Presentation Authors: Takuya Owari*, Makito Miyake, Yoshitaka Itami, Kenta Onishi, Nobumichi Tanaka, Kiyohide Fujimoto, Kashihara-shi, Japan
Introduction: Skeletal-related events (SREs) induced by bone metastasis (BM) can result in reduced QOL, and increased in healthcare burdens. This multi-institutional retrospective study aimed to evaluate the clinical benefit of bone-modifying agents (BMAs) , zoledronic acid and denosumab, and identify risk factors of SREs in patients with genitourinary cancer with BM.
Methods: The study participants included a total of 650 patients with BM of the following cancer types: hormone-sensitive prostate cancer (HSPC; n = 443), castration-resistant prostate cancer (CRPC; n = 50), renal cell carcinoma (RCC; n = 80), and urothelial carcinoma (UC; n = 77). Clinical factors at the time of diagnosis of bone metastasis were analyzed. SREs were defined as pathological fracture, spinal cord compression, or the need for palliative radiotherapy/surgery for BM lesions. Early treatment with BMAs was defined as follows: administration of BMAs before the development of SREs and within 6 months from the diagnosis of BM.
Results: SREs were reported in 88 (20%) patients with HSPC, 17 (34%) patients with CRPC, 58 (73%) patients with RCC, and 34 (44%) patients with UC. Early treatment with BMAs significantly prolonged the time to the first SREs in CRPC, RCC, and UC (p = 0.038, 0.004, and 0.014, respectively), but not in HSPC (p = 0.213) (figure 1). Bone pain, poor performance status, and elevated alkaline phosphatase (ALP) level were independent predictive risk factors of SREs on multivariate analysis. The subgroup analysis revealed that early treatment with BMAs was associated with prolonged time to the first SREs in patients with bone pain or elevated ALP level (figure 2).
Conclusions: Early treatment with BMAs had significantly prolonged time to first SREs in patients with CRPC, RCC, and UC. Early treatment with BMAs should be considered especially for patients with bone pain and elevated ALP level to prevent SREs in patients with GU cancer with BM.