Prevalence and Prognostic Impact of Cancer Cachexia in Patients with Bladder Cancer: A Multicenter Retrospective Study

Background Cancer cachexia is a multifactorial syndrome characterized by progressive skeletal muscle loss and systemic inflammation. Although sarcopenia has been reported as a prognostic factor in bladder cancer, the prevalence and prognostic significance of cancer cachexia defined by standardized criteria remain unclear. Methods We retrospectively analyzed patients who received first-line systemic chemotherapy for urothelial carcinoma at three institutions. Cancer cachexia was defined according to the 2011 European Palliative Care Research Collaborative (EPCRC) criteria based on weight loss, body mass index, and CT-derived L3 skeletal muscle index. Baseline cachexia was assessed within 6 months prior to treatment initiation, and follow-up cachexia was evaluated during treatment. Survival outcomes and prognostic factors were analyzed using Kaplan–Meier methods, logistic regression, and Cox proportional hazards models. Results Among 150 eligible patients, 30% met the criteria for cachexia at treatment initiation. The cumulative prevalence increased to 57.3% within 3 months and reached 74% at some point during the observation period. Cachexia was significantly associated with advanced disease stage and sarcopenia. Overall survival was significantly shorter in patients who developed cachexia, with a median survival of 827 days (95% confidence interval 586–1098). Multivariate Cox analysis identified cancer cachexia and elevated C-reactive protein (CRP) (> 0.4 mg/dL) as independent predictors of poor overall survival. Conclusion Cancer cachexia is highly prevalent in patients with bladder cancer receiving first-line chemotherapy and is independently associated with reduced survival. Early identification of metabolic deterioration may improve risk stratification and guide supportive interventions.