The efficacy and safety of presurgical therapy with tislelizumab and axitinib for renal cell carcinoma with inferior vena cava tumor thrombus.

e16508 Background: There is no currently consensus on presurgical therapy for renal cell carcinoma (RCC) with inferior vena cava (IVC) tumor thrombus. Tyrosine kinase inhibitor (TKI) combined with immune checkpoint inhibitor (ICI) had shown a survival benefit in metastatic RCC patients in clinical trials. However, the efficacy of presurgical therapy with combined ICI and TKI for nonmetastatic RCC with IVC tumor thrombus has not been adequately investigated. Methods: We retrospectively evaluated 7 patients of nonmetastatic RCC with IVC tumor thrombus treated with tislelizumab and axitinib as presurgical therapy and radical nephrectomy and tumor thrombectomy at the First Affiliated Hospital of Xiamen University from May 2020 to December 2022. All patients received combination therapy of tislelizumab and axitinib preoperatively for 3 cycles. The IVC tumor thrombus improvement by Mayo level and diameter were evaluated on magnetic resonance imaging (MRI), and clinical response of primary renal mass and adverse events (AEs) were evaluated using Response Evaluation Criteria in Solid Tumors 1.1 criteria and National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0 criteria. Results: 7 RCC with IVC tumor thrombus patients received neoadjuvant tislelizumab combined axitinib, with a median age of 62 (50-72) years. 71.4% (5/7) were male, 71.4% (5/7) were diagnosed histologically with clear cell RCC, while 28.6% (2/7) were Type I papillary RCC. 57.1% (4/7) were Mayo level 2 tumor thrombus and 42.9% (3/7) were Mayo level 3. At follow-up after systematic therapy, 57.1% (4/7) patients had a reduction in Mayo level of tumor thrombus. The median decrease in thrombus dimeter and length was 5.3 (1.8-17.2) mm and 18.5 (4.4-41.5) mm, respectively. The overall response rate (ORR) in primary renal mass was 57.1% (4/7) with 4 partial responses (PR). Radical nephrectomy and thrombectomy were performed for all 7 patients at 1.5 months after finish of presurgical therapy, with 5 patients performed robotic surgery and 2 patients performed open surgery. 3 patients were planned to have hepatic vein clamping and liver mobilization but following treatment, neither of these manoeuvers was needed. The median operative time was 293 (240-322) minutes, the median blood loss was 1187 (750-2000) mL. The most common AE were all grade 1-2, only 1 patient occurred grade 4 liver function injury which did not affect normal operation after symptomatic treatment. During a median follow-up of 24.9 (14.0-45.0) months, only 1 patient had local IVC tumor thrombus metastasis, disease recovered stabilized after stereotactic radiotherapy. Conclusions: Presurgical therapy with tislelizumab and axitinib for RCC patient could be effective in reducing IVC tumor thrombus and were able to undergo easier radical surgery without serious AE.