Survival Outcomes Associated With Different Palliative Systemic Therapies (Psts) In Patients With Metastatic Bladder Cancer (Mbc)

450 Background: Cisplatin-based (Cis) chemotherapy (C) is considered standard first-line regimen for treating mBC. In individuals medically unfit for Cis, carboplatin-based (Cb) regimens may be considered. Alternative PSTs include immunotherapy (I) as first or second-line treatments. The purpose of this study is to investigate current trends and clinical outcomes of PSTs in patients with mBC. Methods: A retrospective analysis was conducted on patients initially diagnosed with bladder cancer from Sep 2014 to Dec 2016 and had de novo or recurrent mBC. Kaplan-Meier method and Log-Rank test were used to compare survival outcomes among patients receiving different PSTs. Results: In 273 patients, 123 (45.1%) had de novo and 150 (54.9%) had recurrent disease. The median overall survivals (mOS) were 5.3 (95% CI: 3.7-8.2) and 6.5 months (95% CI 5.1-8.9), respectively (p=0.54). Patients received one of the following: C (23.1%), I (6.2%), C followed by I (C/I, 10.6%), and no treatment (NT, 60.1%). The mOS were 9.5 (95% CI: 7.1-12.5), 9.2 (95% CI: 6.1 - not estimable (NE)), 23.9 (95% CI: 16.30-NE), and 3.5 months (95% CI: 3.03-4.30), respectively. Each treatment group had a longer mOS than the NT group (p<0.01 in all three pairwise comparisons). Additionally, patients receiving C/I had a longer mOS than those receiving either C or I (p<0.001 and p=0.0497, respectively). The mOS were not statistically different between C vs I (p=0.2649). In patients receiving any C, 50.0% received Gemcitabine (G) plus Cis and 30.4% received G plus Cb. The mOS were 11.0 (95% CI: 8.7-19.7) and 14.4 months (95% CI:10.7-19.2), respectively, which were not significantly different (p=0.36). Conclusions: Despite the general preference for G plus Cis over Cb, this study showed that G plus Cb as a PST may be a comparable and efficacious treatment. While C currently remains the preferred initial line of PST, patients receiving I had similar survival outcomes to the C group despite many of the patients having Cis ineligibility. Real-world mOS of 2 years in patients who receive both C and I is unprecedented and indicates efficacy of PST. This study provides further evidence for immunotherapy as first or second-line regimen in treating mBC.