Impact of Body Composition, Sarcopenia, Myosteatosis, and Nutritional Status on Recurrence and Progression in Patients With Non-Muscle-Invasive Bladder Cancer: A Prospective Observational Study

Non-muscle-invasive bladder cancer (NMIBC) accounts for approximately 75% of bladder cancer cases and is characterized by a high rate of recurrence and a variable risk of progression. Existing prognostic models, such as EAU and EORTC calculators, incorporate tumor-specific features but do not consider patient-related factors such as body composition or nutritional status. Emerging evidence suggests that sarcopenia, myosteatosis, obesity, and malnutrition may adversely influence oncologic outcomes through mechanisms involving systemic inflammation, impaired immune response, metabolic dysfunction, and reduced physiological reserve. These host-related factors may therefore represent important, yet under-recognized, prognostic biomarkers in NMIBC.

This prospective observational cohort study aims to determine whether clinical and radiologic measures of body composition and nutritional status are associated with the risk of recurrence and progression in patients with NMIBC. Preoperative assessment will include SARC-F screening for sarcopenia, NRS screening for nutritional risk, anthropometric measurements (BMI and waist circumference), serum albumin and testosterone measurement, and CT-based quantification of skeletal muscle index (SMI) and skeletal muscle density (SMD). Tumor-related variables including stage, grade, presence of carcinoma in situ, variant histology, lymphovascular invasion, and tumor size and multiplicity will be abstracted from pathology and clinical records. All participants will undergo standard transurethral resection of bladder tumor (TURBT), and postoperative management will follow guideline-recommended NMIBC surveillance schedules based on individual EAU/EORTC risk stratification.

During follow-up, patients will undergo regular cystoscopic evaluations, urine cytology, serial SARC-F and NRS assessments, anthropometric measurements, albumin monitoring, and periodic CT imaging to reassess SMI and SMD. Recurrence and progression events will be documented according to standard clinical criteria.

By identifying clinically meaningful host-related predictors of recurrence and progression, this study may improve individualized risk stratification, inform tailored surveillance strategies, and highlight the need for early identification and correction of adverse body composition and nutritional states in patients with NMIBC.