Predicting global QoL after orthotopic neobladder or ileal conduit diversion: nomogram development

Introduction - Quality of life (QoL) outcomes in patients undergoing radical cystectomy (RC) with orthotopic neobladder (ONB) or ileal conduit (IC) have been extensively investigated. However, a general lack of consensus on QoL’s predictive factors exists. The aim of the study was to develop a nomogram using preoperative parameters to predict global QoL outcome in patients with localized muscle-invasive bladder cancer (MIBC) undergoing RC with ONB or IC urinary diversion (UD). MethodsA cohort of 319 patients who underwent RC and ONB or IC were retrospectively enrolled. Multivariable linear regression analyses were used to predict the global QoL score of the European Organisation for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ-C30), according to the patient characteristics and UD. A nomogram was developed and internally validated. Results Patients’ data in the two study groups significantly differed with regard to comorbidity profiles (chronic cardiac failure, p < 0.001; chronic kidney disease, p < 0.01; hypertension, p < 0.03; diabetic disease, p = 0.02; chronic arthritis, p = 0.02). A multivariable model that included patient age at surgery, UD, chronic cardiac disease, and peripheral vascular disease represented the basis for the nomogram. The calibration plot of the prediction model showed a systematic overestimation of the predicted global QoL score over the observed scores, with a slight underestimation for observed global QoL scores between 57 and 72. After performing leave-one-out cross-validation, the root mean square error (RMSE) emerged as 24.0. Discussion/conclusionA novel nomogram based completely on known preoperative factors was developed for patients with MIBC undergoing RC to predict a mid-term QoL outcome.