Neoadjuvant Stereotactic Ablative Body Radiotherapy Combined with Surgical Treatment for Renal Cell Carcinoma and Inferior Vena Cava Tumor Thrombus: A Prospective Pilot Study

Background: Surgical treatment for renal cell carcinoma (RCC) and inferior vena cava (IVC) tumor thrombus (TT) is difficult and has a high postoperative complication rate. This study aims to explore the safety and oncologic outcomes of neoadjuvant stereotactic ablative body radiotherapy (SABR) combined with surgical treatment for RCC and IVC-TT. Methods Patients with RCC and IVC-TT were enrolled in this study. All of them received neoadjuvant SABR focused on IVC at a dose of 30 Gy with 5 fractions, followed by 2 ~ 4 weeks of rest. Then, radical nephrectomy and IVC tumor thrombectomy were performed on each patient. Adverse effects, perioperative outcomes, and long-term prognosis were recorded. Results From June 2018 to January 2019, 8 patients were enrolled, including 4 with Mayo II TT and 4 with Mayo III TT. 4 (50%) patients had complicated IVC wall invasion according to CT/MRI. All patients received neoadjuvant SABR as planned. Short-term local controls were observed in all 8 cases. Only grade 1–2 adverse events were reported. In total, 3 (37.5%) laparoscopic surgeries and 5 (62.5%) open surgeries were performed. The median operation time was 359 (IQR: 279–446) min, with a median intraoperative bleeding volume of 750 (IQR: 275–2175) ml. The median postoperative hospital stay was 7 (5–10) days. With a 26 (range: 5–41) month follow-up period, the estimated mean overall survival was 30.67 ± 5.38 months. Conclusions As the first preoperative radiotherapy study in Asia that focused on TT, this study revealed the appreciable safety of neoadjuvant SABR for RCC with IVC-TT. Trial Registration This study was registered in Chinese Clinical Trials Registry in 2018-03-08 (ChiCTR1800015118). For more information, please see the direct link (https://www.chictr.org.cn/showproj.html?proj=25747).