Abstract: Objective To evaluate the efficacy of transcatheter arterial chemoembolization (TACE) for intermediate to advanced hepatocellular carcinoma (HCC) patients with microvascular invasion (MVI) after radical resection. Methods A retrospective analysis was conducted on patients with intermediate to advanced HCC, who were postoperatively diagnosed with revealed MVI through pathological examination, across at five hospitals from January 14,2019 to June 20,2024. The study compared recurrence⁃free survival (RFS), overall survival (OS), and safety between patients who received postoperative TACE and underwent active surveillance. Results In a cohort of 335 included patients, 148 received postoperative TACE and 187 underwent active surveillance. During follow⁃up period, the postoperative TACE group demonstrated a significantly longer median RFS compared to the active surveillance group (15.2 months  vs 12.0 months; HR=0.69, 95%CI: 0.54-0.88, P=0.003). Although the median OS was not reached in the postoperative TACE group, there was a trend toward improved OS relative to the active surveillance group (not reached vs 33.1 months; HR=0.55, 95%CI: 0.40-0.77, P=0.001). Following propensity score matching, the postoperative TACE group demonstrated significantly superior RFS and OS compared to the active surveillance group (all P<0.05). Subgroup analysis based on tumor staging revealed comparable outcomes for patients with intermediate stage HCC in both groups, but significantly improved RFS and OS with advanced stage HCC patients in the postoperative TACE group (all P<0.05). Adverse events associated with postoperative TACE were primarily transient liver injury and nausea/vomiting, with no grade 4 or 5 events reported. Conclusions TACE following radical resection could improve the RFS and OS in some patients with intermediate to advanced HCC exhibiting MVI, particularly in those at advanced stages. However, further prospective randomized trials are crucial to validate these findings.

Key words: Hepatocellular carcinoma, Radical resection, Transcatheter arterial chemoembolization, Microvascular invasion