SUO 2017: Novel Use Of Pre-operative CT-measured Adipose Tissue Indices To Predict Postoperative And Survival Outcomes Among Patients Undergoing Radical Cystectomy

Washington, DC ( Introduction: Obesity is a worldwide epidemic, however the link between obesity and bladder cancer outcomes remains controversial. Studies have suggested that body mass index (BMI) may not be the most accurate measure of obesity.
In this study, the authors measured visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) levels using CT scans prior to radical cystectomy (RC). The authors hypothesized that patients with higher adipose tissue levels would have poorer perioperative and survival outcomes.

Methods: Overall 202 patients undergoing a RC at a single institution were included in this retrospective study (2000- 2012). Multivariable logistic regression analysis was used to generate odds ratios (OR) for predictors of 30-day grade III-V Clavien-Dindo (CD) complications, and linear regression analysis was used to assess predictors of increasing length of stay (LOS). Multivariable competing risks and Cox proportional hazards models were used to assess disease-specific (DSS) and overall survival (OS), respectively.

Results: The median age was 70 (IQR 78-60) years, VAT 165 (IQR 223-114) cm2, SAT- 233 (IQR 316-182) cm2, LOS 9 (IQR 12-7) days, and age-adjusted Charlson Comorbidity Index (CCI) score was 6 (IQR 8-5). 76% of patients were male, and 59% were smokers. There were 32 (16%) 30-day CD grade III-V complications, 71% had ≥pT2-4 disease, and 40% of patients received chemotherapy. Over a median follow-up of 37 (IQR 54-27) months, there were 43 (21%) bladder cancer specific deaths and 65 (32%) all-cause deaths. Adjusting for CCI score and smoking status, VAT was not predictive of grade III-V 30-day CD complications (OR 1.004, 95%CI 0.999-1.008), whereas SAT (OR 1.004, 95%CI 1.001-1.008) was predictive, with similar adjustments. VAT was predictive of increasing LOS (ß-coeff 0.0233, 95%CI 0.0002-0.0463) when adjusted for CCI score and gender, whereas SAT was not (ß-coeff 0.0159, 95%CI -0.0024-0.0342). Neither VAT nor SAT were predictive of DSS or OS on survival analyses.

Conclusion: Higher VAT was predictive of longer post-operative LOS, while SAT was predictive of worse complications (CD III-V) 30 days after RC. There was no difference in cancer-specific or overall survival between groups. VAT and SAT measurements may be useful in conjunction with existing modalities to improve pre-operative risk assessment for predicting immediate post-operative outcomes.

Presented by: Michael Kim, Toronto, Canada

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, @GoldbergHanan, at the 18th Annual Meeting of the Society of Urologic Oncology, November 29-December 1, 2017 – Washington, DC