Combined Transarterial Iodized Oil Injection And Computed Tomography-guided Thermal Ablation For Hepatocellular Carcinoma: The Role Of Iodized Oil Retention Pattern For Prognosis

Objective: To investigate whether the Lipiodol retention pattern can influence treatment efficacy of combination therapy for hepatocellular carcinoma(HCC).Materials and Methods: Between June 2014 and September 2020,a total of 198 patients with 280 HCC lesions who underwent transarterial Lipiodol embolization plus computed tomography(CT)-guided thermal ablation at three medical institutions were included.The Lipiodol retention pattern was classified into complete retention and incomplete retention based on the unenhanced CT at the time of ablation.The primary outcome was local recurrence-free survival(LRFS)for lesions,and the secondary outcome was overall survival(OS)for patients.To reduce the bias of the baseline data between the two group,propensity score matching(PSM)was performed using a caliper width of 0.1between two groups.The differences in LRFS and OS between the two groups were compared with the log-rank test.Stratified subgroup analysis was performed in the 121 matched pairs of lesions.According to the time interval of combined treatment,the lesions were divided into two subgroups: within 1 month and beyond 1 month.According to the tumor size,the lesions was divided into two subgroups: within 3cm and beyond3 cm.The lesions were divided into two subgroups based on whether they were adjacent to vessels or not.According to the endovascular treatment modality,the lesions were divided into two subgroups: pure lipiodol injection(TLI)and conventional chemoembolization(TACE).Results: A total of 133 lesions presented with a complete lipiodol retention pattern,while 147 lesions presented with incomplete retention pattern.After a PSM analysis of the baseline characteristics of the lesions,121 pairs of lesions were matched in each group.The LRFS was significantly higher for lesions with complete retention than for lesions with incomplete retention(P=0.030).After a PSM analysis of the baseline characteristics of patients,74 pairs of patients were matched in each group.There was no significant difference in OS between the two groups(P=0.456).In the subgroup of the interval between TLI/TACE and ablation within 1 month(P=0.015),lesions within 3cm(P=0.022)and TACE combined with thermal ablation(P=0.003),the LRFS of complete lipiodol group was significantly higher than that of incomplete lipiodol retention group.Conclusion: The Lipiodol retention pattern may influence treatment efficacy of combination therapy for HCC lesions.However,a survival benefit of the Lipiodol retention pattern for HCC patients was not observed and needs further confirmation.