Renal cell carcinoma with tumor thrombus growing against the direction of venous return: an indicator of complicated surgery and poor prognosis
Authors: Liu Zhuo , Li Yuxuan , Zhao Xun , Ge Liyuan , Zhu Guodong , Hong Peng , Tang Shiying , Zhang Shudong , Tian Xiaojun , Wang Shumin , Liu Cheng , Zhang Hongxian , Ma Lulin 
Published: April 2021

Abstract
Purpose: To explore the effect of tumor thrombus growing against the direction of venous return (GADVR) tumor thrombus on the choice of surgical approach, the impact on the complexity of the surgery and the prognosis.Methods: We retrospectively analyzed the clinicopathological data of 213 patients, who underwent surgery in a single center of Peking University Third Hospital between January 2016 and June 2020. For right renal cell carcinoma (RCC) and venous tumor thrombus (VTT), imaging revealed a filling defect in the left renal vein, which was significantly enhanced in enhanced imaging, suggesting that the tumor thrombus grew against the direction of venous return into the left renal vein. For left RCC and VTT, at least one of the left renal vein branches has tumor thrombus. The branches include the left adrenal vein, the left gonadal vein (testicular vein or ovarian vein), and the left ascending lumbar vein. The patients were divided into two groups according to whether they were GADVR tumor thrombus, and we compare the clinicopathological characteristics of GADVR tumor thrombus and non-GADVR tumor thrombus. Univariate and multivariate Cox regression analyses were performed to explore the risk factors that affect the prognosis of patients with RCC and VTT. Kaplan-Meier plots were conducted to evaluate the effect of GADVR on progression-free survival (PFS).Results: Compared with non-GADVR tumor thrombus, patients with GADVR tumor thrombus had a higher proportion of open surgery (76.2% vs. 52.1%, P=0.035), a higher proportion of tumor thrombus adhering to the inferior vena cava (IVC) vessel wall (81% vs. 45.8%, P=0.002), a higher proportion of segmental resection of the IVC vessel wall (61.9% vs. 15.6%, P＜0.001); higher preoperative serum creatinine value (110.0μmol/ L vs. 91.0μmol/L, P=0.015), a higher proportion of tumor thrombus combined with bland thrombus (non-tumor thrombus) (57.1% vs. 19.8%, P<0.001). In terms of surgical complexity, patients with GADVR tumor thrombus had a longer median operation time (379.0 min vs. 308 min, P=0.038), more median surgical blood loss (1400ml vs. 600ml, P=0.018), and more postoperative complications (52.4% vs. 30.7%, P=0.045). Multivariate Cox regression analysis showed that GADVR tumor thrombus, symptoms, postoperative serum creatinine, distant metastasis, sarcomatoid feature, pathological type, lymph node dissection were independent risk factors for PFS. Patients with GADVR tumor thrombus's median survival time was 14.0 months, while patients with non-GADVR tumor thrombus were 32.0 months (P = 0.016). GADVR tumor thrombus is an independent risk factor for PFS in patients with RCC and VTT.Conclusion: GADVR tumor thrombus is a characteristic feature of tumor thrombus, with an incidence of 9.9%. It has a higher proportion of open surgery and higher surgical complexity, which is an independent risk factor for PFS.