Radiotherapy directed to inferior vena cava tumor thrombus among patients with renal cell carcinoma: an illustrative case and review of the literature

Renal cell carcinoma (RCC) often presents with tumor thrombus (TT) in the inferior vena cava (IVC), posing significant therapeutic challenges, particularly in cases of metastatic or inoperable disease. While surgical excision remains the standard treatment approach, recent advancements in radiotherapy techniques may offer alternative strategies. We present the clinical picture of a 74-year-old male with metastatic RCC, who presented with recurrent IVC-TT, detected by surveillance computed tomography imaging, and complained of mild lower leg edema. This was successfully managed with stereotactic body radiotherapy (SBRT), resulting in a slow but continuous shrinkage of the IVC-TT with almost complete regression of most lung, liver, and lymph node metastases, obtaining a full resolution of the mild bilateral leg edema. The case described here highlights the possibility of using radiotherapy as a safe and tolerable treatment for inoperable or metastatic patients with IVC-TT. Additionally, we conducted a literature review looking for evidence of the effectiveness of radiotherapy in RCC patients with IVC-TT across different treatment settings. This case-based review ultimately aims to shed light on the emerging evidence supporting the usefulness of radiotherapy in such complex clinical challenges, hopefully paving the way for well-organized trials.