Obesity is associated with worse outcomes in patients with T1 high grade urothelial carcinoma of the bladder.

PURPOSE: To our knowledge the impact of body mass index on oncologic outcomes in nonmuscle invasive bladder cancer has not been evaluated. We hypothesized that higher body mass index is associated with worse outcomes in patients with clinical primary T1 high grade urothelial carcinoma of the bladder.
MATERIALS AND METHODS: We retrospectively analyzed data from 892 patients with primary nonmuscle invasive bladder cancer from 7 centers. Patients were treated with transurethral resection of the bladder with or without intravesical therapy. Body mass index was analyzed as a continuous and a categorical variable (nonobese-body mass index less than 30 kg/m(2) vs obese-body mass index 30 kg/m(2) or greater). Disease progression was defined as the development of T2 or higher tumor stage.
RESULTS: Median followup was 42.8 months (IQR 56). Of the patients 44.3% were obese and median body mass index was 29.2 kg/m(2) (IQR 8). On univariable analyses higher body mass index and age were associated with an increased risk of disease recurrence, progression, cancer specific mortality and any cause mortality (all p ≤ 0.001). On multivariable analyses that adjusted for the effects of gender, concomitant carcinoma in situ, tumor size, number of tumors and intravesical therapy, higher body mass index and age remained independent predictors of disease recurrence, progression, cancer specific mortality and any cause mortality (all p <0.05). This study was limited by its design (ie lack of data on repeat transurethral resection of the bladder and intravesical therapy protocol).
CONCLUSIONS: Patients diagnosed with clinical T1 high grade urothelial carcinoma of the bladder who are obese have worse cancer specific outcomes compared to their nonobese counterparts. Further work is needed to improve our understanding of clinical T1 high grade outcomes in the growing population of obese patients.