Treatment patterns and clinical outcomes of chemotherapy treatment in patients with muscle-invasive or metastatic bladder cancer in the Netherlands.

This retrospective study was performed to evaluate real-world oncological outcomes of patients treated with chemo-based therapy for muscle-invasive or metastatic bladder cancer (MIBC/mBC) and compare results to data from RCTs and other cohorts. Among 1578 patients diagnosed, 470 (30%) had MIBC/mBC. Median overall survival (mOS) for RC alone (47 months), first-line (13 months) and second-line (7 months) chemotherapy, and chemotherapy for recurrent disease (8 months) were similar to literature. Treatment with neoadjuvant and induction chemotherapy (NAIC) was only utilized in 9% of patients, and often in patients with poor disease status, resulting in a lower mOS compared to literature (35 and 20 months, respectively). Patients treated with chemotherapy had many adversities to treatment, with only 50%, 13%, 18% and 7% of patients in NAIC, first-line, salvage after RC, and second-line setting completing the full pre-planned chemotherapy treatment. Real-world data shows NAIC before RC is underutilized. Adversities during chemotherapy treatment are frequent, with many patients requiring dose reduction or early treatment termination, resulting in poor treatment response. Although treatment efficacy between RCTs and real-world patients is quite similar, there are large differences in baseline characteristics and treatment patterns. Possibly, results from retrospective studies on real-world data can deliver missing evidence on efficacy of chemotherapy treatment on older and 'unfit' patients.