Efficacy of selective renal tumor embolization combined with axitinib and reduced-dose toripalimab in oligometastatic clear cell renal carcinoma: A comparative analysis with axitinib combined with standard-dose toripalimab.

532 Background: Oligometastatic renal cell carcinoma (RCC) involves limited metastases (1-5) and lies between localized and metastatic disease, with lower tumor burden. Studies suggest these patients may respond well to local or systemic therapies like targeted or immunotherapy. Combining renal tumor embolization with these therapies is emerging as a promising option. However, comparative data on embolization versus non-embolization treatments remain scarce. This study compares efficacy and adverse events of these treatments in oligometastatic RCC using propensity score matching. Methods: This study included oligometastatic clear cell RCC patients treated since March 2023, divided into two groups. The experimental group received renal tumor embolization, axitinib (5 mg twice daily), and reduced-dose toripalimab (160 mg every 3 weeks). The control group received standard axitinib and toripalimab (240 mg every 3 weeks). All patients had their first follow-up three months post-treatment to assess efficacy and adverse effects. Propensity score matching (PSM) was used to balance demographics, tumor characteristics, and treatment history. The primary outcomes were disease control rate (DCR) and partial response rate (PR), with secondary outcomes being grade 3-4 adverse events. Results: 58 patients were included, 29 in each group after matching. All covariates had SMD values < 0.1, indicating good baseline balance. The experimental group had a DCR of 100% and PR of 93.1%, compared to DCR of 69.8% and PR of 56.7% in the control group (P < 0.05). In 4 patients with renal vein tumor thrombus, tumor size reduced by over 50%, and thrombus control was effective. Grade 3-4 adverse events were lower in the experimental group (10.1% vs. 38.4%, P < 0.05), mainly hypertension, hand-foot syndrome, and liver dysfunction. Conclusions: Propensity score matching showed that renal tumor embolization combined with axitinib and reduced-dose toripalimab improved efficacy and reduced grade 3-4 adverse events in oligometastatic RCC patients. Larger randomized trials are needed to confirm these findings and explore personalized treatment strategies to improve long-term survival and quality of life.