Prognostic role of bland thrombus in patients treated with resection of renal cell carcinoma with inferior vena cava tumor thrombus

1BT is strongly associated with increased level of IVCTT and invasion of IVC wall.2BT is an independent risk factor for both PFS and OS in post-operative RCC-IVCTT.3Patients with BT coexisting with friable tumor thrombus had the worst prognosis.4BT might ameliorate predictive accuracy of TNM staging system.5Routine consideration of BT as an adjunct to TNM staging system may be suggested. To assess the impact of the presence of bland thrombus (BT) on prognosis of patients treated with resection of renal cell carcinoma (RCC) with inferior vena cava tumor thrombus (IVCTT). The medical records of a total of 145 consecutive postsurgical RCC patients with level I-IV IVCTT were reviewed from January 2008 to August 2018. Associations of BT with clinicopathological variables were estimated by chi-square test or Student's t-test. Kaplan-Meier method and multivariate Cox proportional hazard model were used. The eighth TNM staging system, “Spiess PE” model, University of California at Los Angeles Integrated Staging System and Stage, Size, Grade, and Necrosis (SSIGN) score were selected to assess whether BT could improve their predictive abilities. BT was observed in 34 (23.4%) patients and was significantly associated with increased levels of IVCTT (P = 0.004) and invasion of IVC wall (P = 0.030). Multivariable Cox analyses revealed that tumor grade, T stage, M stage, tumor thrombus consistency and BT were independent risk factors for both progression-free survival and overall survival. The concordance indexes ranged from a low of 0.652 in TNM to a high of 0.731 in SSIGN, and integrating BT into each base model led to an increased predictive accuracies of 6.2% for TNM (P = 0.025), 4.0% for “Spiess PE” model (P = 0.069), 2.1% for University of California at Los Angeles Integrated Staging System (P = 0.149) and 1.2% for SSIGN (P = 0.290), respectively. Presence of BT was independently associated with survival in postsurgical patients with RCC-IVCTT. Routine consideration of BT as an adjunct to TNM staging system may be suggested.