Presurgical downstaging of vena caval tumor thrombus in advanced clear cell renal cell carcinoma using temsirolimus.

A 63-year-old man presenting with a 7.2-cm right renal mass, an inferior vena cava tumor thrombus, and pulmonary metastases underwent renal mass biopsy that revealed clear cell renal cell carcinoma. Temsirolimus (25 mg weekly) was given because of the extent of the disease and poor performance status, which resulted in a marked reduction in the tumor thrombus (from level III to level I) after 20 weeks of treatment. Subsequently, radical nephrectomy and tumor thrombectomy were carried out. Final pathological analysis confirmed the diagnosis of high-grade clear cell carcinoma (pT4N0M1). One year after initiation of temsirolimus therapy, the patient remained alive despite the presence of disease.