ABSTRACT
Objective:To explore the independent risk factors of preoperative CT findings affecting the overall survival of patients with clear cell renal cell carcinoma (ccRCC) and to draw a nomogram.Methods:The retrospective study was performed on 238 patients with ccRCC who underwent preoperative CT scan and were pathologically confirmed in First Affiliated Hospital of Air Force Medical University from October 2011 to December 2015. CT findings of each patient were evaluated by two radiologists, and general information, renal function examination, and World Health Organization/International Society for Urology and Pathology (WHO/ISUP) grading were collected. The Kaplan-Meier survival curve was plotted, and survival rates were compared using log-rank test. Cox proportional hazard regression was used for univariate and multivariate analysis, and the nomogram was drawn according to the results of multivariate analysis, and the C-index was calculated after internal validation by Bootstrap 1000.Results:After 3-74 months of follow-up for 238 patients, 32 cases were in the death group and 206 cases were in the censored group. The tumor diameter of the death group [(65.70±27.29) mm] was larger than that of the censored group [(46.25±26.16) mm], with a statistically significant difference ( t=-3.889, P<0.001). The incidence rate of tumor necrosis ( χ2=45.716, P<0.001), regional lymph node enlargement ( χ2=43.342, P<0.001) and perirenal fat invasion ( χ2=19.324, P<0.001) in the death group were higher than those in the censored group. Survival rates were different in patients with different tumor diameter of ccRCC, with a statistically significant difference ( χ2=17.108, P<0.001). The survival rate of patients with tumor necrosis was lower than those without necrosis ( χ2=48.195, P<0.001). The survival rate of patients with regional lymph node enlargement was lower than those without regional lymph node enlargement ( χ2=47.232, P<0.001). The survival rate of patients with perirenal fat invasion was lower than those without perirenal fat invasion ( χ2=19.964, P<0.001). Survival rates were also different in ccRCC patients with different WHO/ISUP grades, with a statistically significant difference ( χ2=27.765, P<0.001). In Cox multivariate analysis, tumor diameter ( HR=2.90, 95% CI: 1.37-6.14, P=0.006), necrosis ( HR=8.88, 95% CI: 3.33-23.69, P<0.001) and regional lymph node enlargement ( HR=4.48, 95% CI: 2.04-9.86, P<0.001) in CT findings were independent risk factors for death in patients with ccRCC. The C-index of nomogram was 0.870. Conclusion:Preoperative CT findings are correlated with survival rate of patients with ccRCC, in which tumor diameter, tumor necrosis and regional lymph node enlargement are independent risk factors for death, and the nomograms has high accuracy.