Mortality after Radical Cystectomy: Impact of Obesity Versus Adiposity after Adjusting for Skeletal Muscle Wasting

Abstract

Purpose We assess the impact of obesity, as measured conventionally by body mass index vs excess adiposity as measured by fat mass index, on mortality after radical cystectomy for bladder cancer, adjusting for the presence of skeletal muscle wasting. Materials and Methods This retrospective cohort study included 262 patients treated with radical cystectomy for bladder cancer between 2000 and 2008 at the Mayo Clinic. Lumbar skeletal muscle and adipose compartment areas were measured on preoperative imaging. Overall survival was compared according to gender specific consensus fat mass index and skeletal muscle index thresholds as well as conventional body mass index based criteria. Predictors of all cause mortality were assessed by multivariable modeling. Results Increasing body mass index correlated with improved overall survival (p=0.03) while fat mass index based obesity did not (p=0.08). After stratification by sarcopenia, no obesity related 5-year overall survival benefit was observed (68% vs 51.4%, p=0.2 obese vs normal and 40% vs 37.4%, p=0.7 sarcopenia vs sarcopenic/obese). On multivariable analysis class I obesity according to body mass index (HR 0.79, p=0.33) or fat mass index criteria (HR 0.85, p=0.45) was not independently associated with all cause mortality after adjusting for sarcopenia (HR 1.7, p=0.01) as well as age, performance status, pTN stage and smoking status. However, in patients with normal lean muscle mass each 1 kg/m2 increase in weight or adipose mass was associated with a 7% to 14% decrease in all cause mortality. Conclusions After adjusting for lean muscle wasting, neither measurements of obesity nor adiposity were significantly associated with all cause mortality in patients treated with radical cystectomy, although subanalyses suggest a potential benefit among those with normal lean muscle mass.

Influence of Body Mass Index on Clinical Outcome Parameters, Complication Rate and Survival after Radical Cystectomy: Evidence from a Prospective European Multicentre Study

“…This can surely cause differences in the indication for RC, extent of lymphadenectomy, histopathological assessment or quality of TUR-BT. Moreover, by investigating BMI we cannot distinguish between fat and muscle, as BMI is not an anthropometric measure that can assume body composition [31]. In addition to body composition, sarcopenia as a surrogateparameter of frailty was not assessed and therefore, the model was not adjusted for it [32].…”

Preoperative nutritional factors and outcomes after radical cystectomy: A narrative review

“…More than 80% accrued nutritional data retrospectively, similar to the 87% reported in 2007 52 . Psutka et al 41 conducted sensibility analysis to test for possible bias introduced by the exclusion of patients with missing data, but this was unfortunately not discussed in the majority of the literature reported here. Many studies also observed the impact of BMI on complications and mortality after RC using regression models.…”

“…Twelve studies investigated the association between BMI and RC outcomes [33][34][35][36][37][38][39][40][41][42][43][44] . Reyes et al 33 found that tract infections, pyelonephritis, wound infections and overall complications were less frequent in normal-weight patients (18.5-24.9kg/m 2 ) compared to overweight (25-29.9kg/m 2 ) and obese (≥30.0kg/m 2 ) patients.…”

“…Psutka et al 41 investigated the impact of BMI and fat mass index on mortality after RC at the Mayo Clinic in Minnesota in 515 RC subjects from 2000-2008. Higher BMI was associated with improved overall survival, while fat mass index was not.…”

Preoperative sarcopenia status is associated with lymphovascular invasion in upper tract urothelial carcinoma patients treated with radical nephroureterectomy

“…Previous studies described sarcopenia as a novel prognostic factor for predicting survival in patients with various cancers, including colorectal cancer, pancreatic cancer, hepatocellular carcinoma, renal cell carcinoma, UC, and gastroesophageal cancer. [2][3][4][5][6][7] Only two studies have investigated the relationship between the sarcopenia status and clinical outcomes of UTUC patients treated with RNU.…”