Early Bone Metastases are Associated with Worse Outcomes in Metastatic Urothelial Carcinoma

BACKGROUND: Outcomes of patients with metastatic urothelial carcinoma (mUC) with early bone metastases (eBM) vs no early bone metastases (nBM) have not thoroughly been described in the age of immuno-oncology. OBJECTIVE: To compare survival and other clinical outcomes in patients with eBM and nBM. METHODS: We used a multi-institutional database of patients with mUC treated with systemic therapy. Demographic, metastatic site, treatment patterns, and clinical outcomes were recorded. Wilcoxon rank-sum, chi-square tests were performed. Survival was estimated by Kaplan-Meier method; multivariable Cox analysis was performed. RESULTS: We identified 270 pts, 67% men, mean age 69±11 years. At metastatic diagnosis, 27% had≥1 eBM and were more likely to have de novo vs. recurrent metastases (42% vs 19%, p < 0.001). Patients with eBM had shorter overall survival (OS) vs. those with nBM, (6.1 vs 13.7 months, p < 0.0001). On multivariable analysis, eBM independently associated with higher risk of death, HR = 2.52 (95% CI: 1.75-3.63, p < 0.0001). OS was shorter for patients with eBM who received initial immune checkpoint inhibitor vs platinum-based chemotherapy, (1.6 vs 9.1 months, p = 0.02). Patients with eBM received higher opioid analgesic doses compared to patients with nBM and received quantitatively more palliative radiation. CONCLUSIONS: Patients with mUC and eBM have poorer outcomes, may benefit less from anti-PD-1/PD-L1 therapy and represent an unmet need for novel therapeutic interventions. Dedicated clinical trials, biomarker validation to assist in patient selection, as well as consensus on reporting of non-measurable disease are required.