Abstract:Objective To explore the effects of transcatheter arterial chemoembolization (TACE), local thermal ablation and intravenous chemotherapy on the immune function and serum cytokines of patients with liver metastasis after colorectal cancer surgery. Methods A total of 81 patients with oligometastatic liver metastases after colorectal cancer surgery were enrolled and randomly assigned to three groups (27 patients per group): TACE, thermal ablation, and intravenous chemotherapy. Magnetic resonance examination was performed 1 month after treatment to evaluate the short-term efficacy. Peripheral blood was collected before treatment and one month after treatment for immune cell and measurement of 12 cytokines. The intravenous chemotherapy group was served as the control, and the effects of TACE and thermal ablation on immune function and cytokines were compared. Results The response rate (RR) of thermal ablation group (96.30%), TACE group (55.56%) and intravenous chemotherapy group (29.63%) were significantly different (χ²=25.519, P<0.01), and the RR of the thermal ablation group was higher than that of TACE group and intravenous chemotherapy group, respectively (P<0.017). One month after treatment, the percentages of CD4⁺ and natural killer (NK) cell, and the CD4⁺/CD8⁺ ratio increased significantly in both the thermal ablation group and TACE group compared to pre-treatment (P<0.05), while the percentages of CD8 + and Treg cell decreased (P<0.05). In contrast, no significant change was observed in the intravenous chemotherapy group (P>0.05). The greatest impact on immune function was observed in the thermal ablation group, followed by the TACE group, and the least in the intravenous chemotherapy group (P<0.05). After treatment, interleukin (IL) -5 and IL-6 levels were decreased in all three groups, and the level of IL-1β in the thermal ablation group decreased compared to preoperative level (P<0.05). Thermal ablation had a more significant impact on serum cytokines than that of TACE and intravenous chemotherapy. Conclusion TACE and thermal ablation interventional local therapy can improve the short-term RR and immune function of patients with liver oligometastasis after colorectal cancer surgery, especially thermal ablation. TACE and thermal ablation therapy may play an active role in the anti-tumor immune response by affecting serum cytokines.