Conversion therapy for initially unresectable intrahepatic cholangiocarcinoma: A multicenter real-world study.

4118 Background: Currently, studies on conversion therapy for intrahepatic cholangiocarcinoma (ICC) are relatively limited. Effectiveness and optimization strategies of conversion therapy in real world remain unclear. This study aims to analyze the efficacy of locoregional combined with systematic therapy in patients with unresectable ICC, optimizing conversion therapy strategies by retrospectively. Methods: In this multicenter retrospective study, patients with unresectable ICC who received hepatic arterial infusion chemotherapy combined with ICIs and target therapy were reviewed. Overall survival (OS), progression-free survival (PFS) , objective response rate (ORR) , disease control rate(DCR)(assessed by mRECIST criteria) and safety were analyzed. Results: Between June 2018 to May 2024,a total of 341 patients from six centers were included in this study. The median follow-up time was 21.7 months.Among them, 313 patients with complete imaging evaluations are eligible for efficacy analysis. Of which, 20 patients achieved complete response (CR), 93 patients partial response (PR), 161 patients stable disease (SD), illustrating an ORR of 36.1% and a DCR of 87.5%. Among them, 65 patients successfully underwent conversion surgery, with a median duration of conversion therapy of 4.1 months. Radical resection was achieved in 39 patients within the surgical cohort, and 3 patients demonstrated pathological CR. Systemic therapy regimens with the highest conversion success rates included apatinib plus toripalimab (42.9%), lenvatinib plus tislelizumab (32.4%), and apatinib plus tislelizumab (30.8%). Patients with tumor diameters less than 10 cm and those with unilobar tumor were more likely to achieve successful conversion. After propensity score matching (PSM) to balance baseline characteristics (ratio = 1, caliper = 0.01), the surgical group exhibited better survival outcomes compared to the non-surgical group (not reached vs. 27.2 months, hazard ratio: 0.36, 95% CI: 0.61–0.81, p = 0.001). The median PFS was 13.0 months in the surgical group versus 8.0 months in the non-surgical group (hazard ratio, 0.57; 95% CI, 0.30 to 1.09; p = 0.088).Within the surgical cohort, the 2-year survival rates for patients with palliative surgery and radical resection were 51.3% and 26.9%, respectively ( p = 0.051). All patients experienced treatment-related adverse events (TRAEs), but no treatment-related deaths occurred. The incidence of Grade 3-4 TRAEs was 28.6%. Conclusions: Locoregional combined with systemic therapy is an effective strategy for conversion treatment. Conversion surgery offers substantial survival benefits, while palliative surgery may also serve as a viable therapeutic option.