Background  Microwave ablation (MWA) is one of the main treatments for hepatocellular carcinoma (HCC). However, it is still unclear whether an increased number of MWA sessions are associated with a higher risk of liver injury in patients with recurrent HCC.

  Objective  To investigate the effect of repeated MWA on postoperative liver function of HCC patients.

  Methods  Clinical data about HCC patients who underwent percutaneous MWA in the Fifth Medical Center of Chinese PLA General Hospital from June 2016 to July 2021 were retrospectively analyzed. According to the times of MWA treatment, HCC patients were divided into group A (single MWA treatment) and group B (multiple MWA treatments). Liver function indices before MWA, 24 h and 5-7 d after MWA were collected, together with postoperative complications. The Albumin-Bilirubin (ALBI) grade was used to assess postoperative liver function in HCC patients. Liver function and complications after ablation were compared between the two groups.

  Results  A total of 223 HCC patients were enrolled, including 183 males and 40 females with an average age of (58.99 ± 9.17) years. Among them, 142 cases were in group A and 81 cases in group B. There was no significant difference in general information and clinical features between the two groups (P>0.05). The distribution of aspartate aminotransferase (AST) in the two groups was similar before MWA and 5-7 d after MWA, but it was significantly lower in group B than group A at 24 h after MWA (MdIQR: 247148 ~ 370 U/L vs 287205 ~ 406 U/L, P=0.037). There was no significant difference in the distribution of prothrombin activity (PA), albumin (ALB), total bilirubin (TBIL), alanine aminotransferase (ALT) and cholinesterase (ChE) before MWA, 24 h and 5-7 d after MWA between group A and group B. At 24 h after MWA, ALB in group B and ChE in both groups decreased slightly compared with those before MWA, with no statistical significance (P>0.05). The other liver function indices in the two groups 24 h and 5-7 d after MWA were slightly worse than those before MWA (P<0.01). The ratio of ALBI grade deterioration after MWA in group A and group B was similar (P>0.05). There was no significant difference in the incidence of fever, hepatic pain and major complications (including major infection, pleural effusion and ascites, bleeding and liver failure) between the two groups after MWA (P>0.05).

  Conclusion  MWA is a safe, effective and repeatable treatment for patients with HCC and an increased number of MWA sessions will not increase postoperative hepatic insufficiency and complications.