**8. IVC tumor thrombus with thrombosis and treatment recommendations**

Vena cava tumor thrombus with thrombosis is common. The prevalence of thrombosis gathered by the Urological Department of Chinese PLA General Hospital is 19.2%. Thrombosis, at the same time, is not found within the renal venous tumor thrombus; all thrombosis occurred in the vena cava tumor thrombus. Among them, vena caval thrombi were all located on the right, the thrombus was located in the distal end of the tumor thrombus, and the distal thrombus could reach the bifurcation of the iliac vessel. Preoperative MRI can help determine the location and length of the thrombus.

Preoperative anticoagulation therapy is recommended for patients with thrombosis, and medication should be administered from the diagnosis of tumor thrombus and thrombus. Low-molecular heparin is recommended for anticoagulation therapy, withdrawing drugs 24 h preoperatively, maintaining the international normalized ratio of 2–3, and anticoagulation therapy is continued for 48 h postoperatively and maintained for 6 months, except for the following: patients with tumor or tumor thrombus who did not undergo complete resection; those with metastasis; needs for systemic treatment; and patients with pulmonary embolism. Pre- and postoperative placement of the vena cava stent is not recommended only if the patient has pulmonary embolism and contraindications of anticoagulation therapy [41, 42]. Preoperative imaging examinations are required for patients with extensive thrombosis at the distal end of the tumor thrombus [43]. IVC interruption is recommended, which prevents embolization caused by thrombus shedding, for patients who meet the indications and possess sufficient collateral circulation.
