(UroToday.com) Venous tumor thrombus extension occurs in 4-15% cases of renal cell cancer (RCC). The Mayo classification distinguishes four levels of venous tumor thrombus extension between the renal vein and supradiaphragmatic inferior vena cava. Although surgery is performed with curative intent, mortality is high (5-15%) with complications increasing with the level of the venous tumor thrombus. Ultimately, 5-year survival rates are poor in these patients at ~40-65% if they are non-metastatic at the time of surgery. It is hypothesized that neoadjuvant targeted therapy could downstage the venous tumor thrombus reducing the extent of surgery, leading to reduced surgical morbidity and mortality, and increased survival. However, level I or II evidence is lacking. The NAXIVA trial provides the first level II evidence in this patient group, assessing the response of venous tumor thrombus to axitinib. At the Renal Cell Cancer Rapid Abstract Session at the 2021 American Society of Clinical Oncology (ASCO) Genitourinary (GU) Cancers Symposium, Dr. Grant Stewart and colleagues presented results of the NAXIVA Phase II trial.