Emerging clinical phenotype of bone metastatic urothelial cancer (mUC): Association of early osseous metastases (EOM) and outcomes.

Abstract

e17007 Background: Outcomes of patients (pts) with mUC with EOM have not thoroughly been described in the age of immuno-oncology. We hypothesized that EOM is associated with worse outcomes when compared to pts with non-osseous metastases (NOM). Methods: We used a multi-institutional database of pts with mUC who received systemic treatment (trt) between March 2005 and August 2019, to assess survival and palliative outcomes of pts with EOM vs NOM at the time of metastatic diagnosis (met dx). Wilcoxon rank-sum and chi-square tests were performed. Survival was estimated by Kaplan-Meier method, Cox regression analysis was performed. Results: We identified 270 pts, 72% men, mean age 67 ± 11 years, 28% never smokers. At met dx, 27% (n = 72) had ≥ 1 EOM; these pts were more likely to have de novo metastases vs. those with recurrent metastases (42% vs 19%, p < 0.001). Pts with EOM were more likely to have a change or stop in 1st line trt due to clinical progression (30.6% vs 15.7%, p = 0.006), and received fewer total lines of systemic trt, median of 1.0 (1.0-5.0) vs. 2.0 (1.0-8.0), p = 0.05. Pts with EOM had shorter median overall survival (OS) vs. those with NOM, (6.1 vs 13.7 months, p < .0001), HR = 2.79 (95% CI:1.95-3.97, p < .0001). Median OS was shorter for pts with EOM who received 1st line immune checkpoint inhibitor (n = 14) vs platinum-based chemotherapy (n = 43), (1.6 vs 9.1 months, p = 0.003). Pts with EOM received higher opioid analgesic doses at the first and last oncology outpatient visits compared to pts with NOM with mean morphine milligram equivalent (MME) dose of 60 ± 91 vs 28 ± 65 at first visit, p = 0.004, and 171 ± 214 vs. 94 ± 229 at last visit, p < 0.001. Conclusions: The presence of EOM in mUC is associated with worse outcomes vs. pts with NOM. Pts with EOM may benefit from 1st line platinum-based chemotherapy vs. checkpoint immunotherapy. Furthermore, pts with EOM experience more pain than pts with NOM and may benefit from early engagement with palliative care. Pts with EOM represent a population with a highly unmet need for systemic, targeted and/or radiation interventions. Molecular subtypes may further define these pts and analysis is planned. We encourage ongoing clinical trials to report outcomes in pts with EOM. A consensus on reporting of non-measurable disease is also needed. [Table: see text]