Development of a new outcome prediction model in carcinoma invading the bladder based on preoperative serum C-reactive protein and standard pathological risk factors: the TNR-C score

Abstract

What's known on the subject? and What does the study add? There is increasing evidence for a prognostic significance of pretherapeutically elevated serum C-reactive protein levels in various cancers. However, little is known about its significance in patients with invasive bladder cancer. This study shows that serum CRP is an independent predictor for cancer-specific survival in bladder cancer, and its incorporation into a new outcome model (TNR-C Score) encompassing major pathological determinants for survival, increases significantly its predictive accuracy.

Objective: • To assess the predictive value of preoperative C-reactive protein (CRP) in patients undergoing radical cystectomy (RC) for carcinoma invading the bladder in light of recent data showing it to be an independent indicator of adverse oncological outcome in other malignancies.

Patients and methods: • A contemporary, consecutive series of 246 patients undergoing RC and bilateral pelvic lymphadenectomy for bladder cancer between 1999 and 2009. • Elevated CRP was defined as >0.5 mg/dL and was consistent during the study period. The median (range) follow-up was 30 (6-116) months. • Kaplan-Meier analysis was used to estimate cancer-specific survival (CSS) using a log-rank test and Cox regression analysis for multivariate analysis of risk factors. • Based on regression estimates of significant parameters in multivariate analysis, a new CRP-based scoring model was developed to predict cancer-specific outcomes. The predictive accuracy of the model was evaluated using the concordance index.

Results: • The 3-year CSS was 74.0% in patients with normal and 44.0% with elevated CRP (P < 0.001). • In multivariate analysis, CRP (P < 0.001; used as a continuous variable), tumour stage (P= 0.001), lymph-node density ≥0.09 (P= 0.02) and resection margin status (P < 0.001) were independent predictors of CSS. • The 3-year CSS in patients with a score in the ranges 0-2, 3-6 and 7-10 was 80.5%, 44.9% and 7.1%, respectively (P < 0.001). Consideration of CRP in the final model increased its predictive accuracy by 4.9% with a concordance index of 0.788 (P= 0.01).

Conclusions: • This is the largest, contemporary series to date indicating that preoperative serum CRP is an independent risk factor for CSS. • CRP may be a useful parameter to include in predictive bladder cancer nomograms.