The Important Role of Tumor Volume In Surgical Approach Choice, Surgical Complexity, and Post-Operative Complications In Renal Cell Carcinoma With Venous Tumor Thrombus From A Large Chinese Center Experience
Authors: Baheen Qais A. , Liu Zhuo , Hao Yichang , Sawh Rejean R.R. , Li Yuxuan , Zhao Xun , Ma Lulin 
Published: April 2021

Abstract
Background: To evaluate the significance of interactions between tumor volume (TV) and surgical approach choice, surgical complexity, intra-operative blood loss, post-operative complications, as well as overall survival (OS) for patients with inferior vena cava tumor thrombus (IVCT-T) in locally advanced renal cell carcinoma (RCC). Method: From Jan 2014 to Jan 2020, we identified 132 patients who underwent radical nephrectomy with inferior vena cava thrombectomy (RN-IVCT) in Peking University Third Hospital (PKUTH) and had available imaging for review. TV for RCC, renal vein (RV) and IVCT were separately measured through the well-known and commonly used application by medical professions，3D slicer. The significance of differences between groups was evaluated using linear regression. Prognostic factors were identified by univariate and multivariate analyses using the Cox proportional hazards model, and hazard ratios (HRs) with 95% confidence intervals were calculated. Results: Patients were divided into three groups based on the inferior vena caval tumor thrombus volume (IVCT-TV); group 1 comprised of all patients with IVCT-TV between 0-15 cubic centimeter (cm3), group 2 comprised of all patients with IVCT-TV between 15-30 cm3, and group 3 comprised of all patients with IVCT-TV greater than 30 cm3. Using these criteria, there were 48 patients in group 1, 38 in group 2, and 46 in group 3, representing 36.6%, 28%, and 35% of the total number of patients, respectively. There were 24 patients with Mayo grade I, 74 patients with Mayo grade II, 19 patients with Mayo grade III, and 18 patients with Mayo grade IV. Fifty-nine patients (44.7%) underwent complete laparoscopic surgery, and 73 patients (55%) underwent open surgery. The median surgery time was 334 minutes for group 1, 341 minutes for group 2, and 374 minutes for group 3 (p <0.044). The median intra-operative blood loss was 650 ml for group 1, 600 ml for group 2, and 2350 ml for Group 3 (p <0.001). Post-operative complications occurred in 13 (27.1%) patients from group 1, 15 (39.5%) patients from group 2, and 35 (76.1%) patients from group 3 (p < 0.001). Open approach surgery was the more desirable choice for caval tumor group (p< 0.001) and total thrombi volume group (P<0.001). Overall surgery time was significantly longer, and operation was more difficult for renal venous thrombus volume group (P < 0.014), caval tumor volume group (P <0.033), and total thrombi volume group (P <0.005). Intra-operative blood loss was more and statistical difference was seen for caval tumor volume (p<0.001) and total tumor volume (p<0.001). No significant difference was noted for a demographic characteristic such as age, gender, side, size, BMI index, tumor type. Operative time, intra-operative blood loss, depth of IVC vascular wall invasion, surgical approach, and Mayo level were identified as the independent factors in this study. Conclusion: Results of this present study indicate that a larger TV necessitates open surgery approach, and is associated with a prolonged operative time, increased intra-operative blood loss, increased surgical complexity, and a higher incidence of post-operative complications. However, TV does not affect the overall patient survival and hospitalization time.