Evaluation of sarcopenia in patients receiving intravesical Bacillus Calmette-Guérin for non-muscle invasive bladder cancer

Abstract

Background: Sarcopenia is associated with adverse outcomes for patients with muscle invasive bladder cancer (MIBC), but less is known about its impact in the setting of non-muscle invasive bladder cancer (NMIBC). Sarcopenia, skeletal muscle density, and adipose tissue area have been studied as markers of malnutrition and can be determined radiographically. The purpose of this study is to characterize the prevalence of sarcopenia in patients with NMIBC receiving intravesical Bacillus Calmette-Guérin (BCG).

Methods: Following institutional review board approval, patients with NMIBC having received intravesical BCG were identified using institutional pharmacy records. Patients having undergone computed tomography (CT) of the abdomen and pelvis within 90 days of treatment were included in the analysis. Using sliceOmatic 5.0 software, skeletal muscle area (cm²) was measured at the L3 level to calculate skeletal muscle index (SMI), a marker of sarcopenia. Subcutaneous, visceral, and intramuscular adipose tissue areas in addition to skeletal muscle density were also measured. Frailty was evaluated as a secondary aim using the 5-Item Modified Frailty Index (mFI-5). Using predefined cutoffs, the prevalence of sarcopenia was determined. Descriptive statistics were used to characterize frailty and secondary body composition characteristics. Statistical analysis was performed to evaluate the impact of sarcopenia on recurrence rate and progression.

Results: A total of 308 patients having received BCG between 2015 and 2020 were identified, of which 90 met criteria for analysis. Nearly all (94%) patients completed at least 5 out of 6 BCG induction instillations. Median body mass index (kg/m²) was 27.64 (IQR 24.9, 30.5) for females and 27.7 (IQR 24.9, 30.66) for males. Median SMI (cm²/m²) was 49.44 (IQR 39.39, 55.17) for females and 49.58 (IQR 40.25, 55.58) for males. A majority (61%) of patients were found to be sarcopenic. High-risk frailty was identified 36% of patients. There was no association between sarcopenia and recurrence rate or progression.

Conclusions: Sarcopenia and frailty are highly prevalent amongst patients with NMIBC. A diagnosis of NMIBC represents a window of opportunity to identify and intervene on modifiable risk factors such as sarcopenia and frailty, which are associated with adverse outcomes in more advanced disease states.

Keywords: Body composition; Local; Malnutrition; Neoplasm recurrence; Sarcopenia; Urinary bladder neoplasms.