This study aimed to preliminarily evaluate the clinical efficacy and safety of hepatic arterial infusion chemotherapy (HAIC) of gemcitabine and oxaliplatin (GEMOX) plus systemic gemcitabine chemotherapy (GEM-SYS) combined with lenvatinib and programmed cell death protein-1 (PD-1) inhibitor in patients with large unresectable intrahepatic cholangiocarcinoma (uICC). Large uICC patients who underwent GEMOX-HAIC (Day 1) and GEM-SYS (Day 8) (3w/cycle) combined with lenvatinib and PD-1 inhibitor between November 2019 and December 2022 were enrolled. Clinical data were retrospectively collected to analyze local tumor response, progression-free survival (PFS), overall survival (OS), and adverse events (AEs). Tumor response was assessed by the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. AEs were evaluated by the common terminology criteria for adverse events (CTCAE) version 5.0. In this study, OS was the primary endpoint, and progression-free survival (PFS) was the secondary endpoint.

Inclusion Criteria:

(a) age of 18-70 years; (b) Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1; (c) diagnosis of ICC by histopathological examination of tissue biopsy specimens; (d) unresectable ICC confirmed by a multidisciplinary staff including at least one experienced liver surgeon; (e) tumor size larger than 5 cm in maximum diameter; (f) adequate liver function (total bilirubin < 3 times the upper limit of normal and aspartate/alanine transaminases < 5 times the upper limit of normal), adequate renal function (serum creatinine concentration of no more than 1.5 times the upper limit of the normal level), adequate bone marrow function (white blood cell count>3,000/mm3, hemoglobin>9.0g/dl and platelet count >100,000/mm3 ) and adequate coagulation function (prothrombin activity > 40% and international normalized ratio (INR) < 1.26); (g) patients received at least two cycles of GEMOX-HAIC + GEM-SYS combined with lenvatinib and PD-1 inhibitor; (h) patients with regular clinical data for evaluating the clinical efficacy and safety.

Exclusion Criteria:

(a) combined with other malignancies; (b) patients underwent any other chemotherapy regimens before, including gemcitabine and oxaliplatin; (c) patients received previous surgical resection or any other interventional procedures besides HAIC, such as transarterial chemoembolization (TACE), 125I seed implantation, radiofrequency ablation, microwave ablation, cryoablation, or percutaneous ethanol injection, etc.; (d) drug (chemotherapy drugs, lenvatinib, or PD-1 inhibitors) allergy; (e) patients with a history of autoimmune diseases; (f) patients with gastrointestinal bleeding of any grade within 4 weeks prior to the integrated treatment; (g) patients with uncontrolled comorbidities (e.g. general infection, serious dysfunction of heart or kidney, acute hepatitis or pneumonia, chronic obstructive pulmonary disease, or recent stroke).

21 large uICC patients who underwent GEMOX-HAIC (Day 1) and GEM-SYS (Day 8) (3w/cycle) combined with lenvatinib and PD-1 inhibitor between November 2019 and December 2022 were enrolled.