Association of radical cystectomy and increased risk of skeletal-related events in bone-metastatic urothelial carcinoma.

Abstract

477 Background: Bone metastases are common in patients with advanced cancer of the bladder or upper urinary tract; however, few studies have assessed the morbidity of bone metastases in these patients. We sought to characterize bone-associated morbidity by measuring the frequency of skeletal-related events (SREs) and identify predictors of SREs in this population. Methods: We retrospectively identified 328 patients with bone-metastatic bladder or upper urinary tract cancer managed at Memorial Sloan Kettering between 2000 and 2018. SREs were defined as presence of spinal cord compression from bone metastasis, pathologic fracture, treatment of bone metastasis with radiotherapy or surgery, or hypercalcemia of malignancy. SRE-free survival was estimated using Kaplan-Meier analysis; competing-risks regression analysis was used to identify predictors of SREs. Results: In total, 198 patients (60%) developed ≥1 SRE, including 84 (26%) with multiple SREs. The most common SREs were bone radiotherapy (n=165 [83%]), pathologic fracture (n=73 [37%]), and orthopedic surgery (n=39 [20%]). Median SRE-free survival was 7.4 months. On competing-risks regression analysis, history of radical cystectomy (hazard ratio [HR], 1.40; 95% CI, 1.05-1.86; P=0.02) and hip involvement at the time of bone metastasis diagnosis (HR, 1.65; 95% CI, 1.12-2.42; P=0.01) were independently associated with risk of SRE. Conclusions: SREs are common among patients with bone-metastatic cancer of the bladder or upper urinary tract and typically occur soon after the development of bone metastasis. Patients with a history of radical cystectomy or with hip involvement at the time of bone metastasis diagnosis have a higher risk of SRE.