Abstract
Renal cell carcinoma (RCC) with inferior vena cava tumor thrombus (IVCTT) remains a major clinical challenge. Venous outflow obstruction from the thrombus can precipitate severe lower-extremity edema and secondary deep vein thrombosis (DVT). Current guidelines do not recommend routine placement of inferior vena cava filters (IVCFs) in this setting because progressive tumor thrombus may increase the risk of filter migration and can worsen thrombosis. Here, we report a 52-year-old man with right RCC and a level II IVCTT (Mayo classification) complicated by extensive iliofemoral DVT. He was treated using a combined interventional strategy that included endoluminal brachytherapy with long iodine-125 (^125I) seed strands, catheter-directed thrombolysis (CDT), and renal artery embolization (RAE). After treatment, inferior vena cava outflow improved markedly, and swelling of the lower limbs and scrotum resolved. Follow-up imaging demonstrated substantial regression of the tumor thrombus and a reduced renal tumor burden. To overcome the limitations of inadequate intraluminal dose coverage and the technical difficulty of safely implanting seeds directly within a mobile tumor thrombus, we used two self-designed long ^125I seed strands that were securely anchored at the jugular venous access region to deliver continuous, localized irradiation to the IVCTT. CDT and RAE were applied to further reduce thrombus and tumor volume and were associated with a favorable clinical response in this patient. The patient remained alive without disease progression for more than 39 months from diagnosis. This case illustrates the potential role of a multimodal interventional approach for simultaneous control of IVCTT and venous thrombosis and highlights the feasibility of endoluminal brachytherapy using radioactive seed strands as a strategy to manage complex RCC with IVCTT.