Severity grading of microvascular invasion predicts oncological outcomes following hepatectomy for unresectable hepatocellular carcinoma converted by tyrosine kinase inhibitors plus anti-PD-1 antibodies

The prognostic significance of microvascular invasion (MVI) in patients undergoing hepatectomy following conversion therapy with tyrosine kinase inhibitors (TKIs) combined with anti-PD-1 antibodies for initially unresectable hepatocellular carcinoma (uHCC) remains unclear. This study aimed to investigate the association between the grading severity of MVI and oncological outcomes in this population. Patients with uHCC who underwent hepatectomy after conversion therapy with TKIs and anti-PD-1 antibodies were studied from a multicenter database. Patients were categorised into three groups based on the grading severity of MVI: M0 (no MVI), M1 (1–5 MVI foci ≤ 1.0 cm from the tumor), and M2 (> 5 MVI foci ≤ 1.0 cm and/or any MVI foci > 1.0 cm from the tumor). Recurrence-free survival (RFS) and overall survival (OS) were compared among the groups. Among 101 uHCC patients, 62, 21, and 18 patients were identified in the M0, M1, and M2 groups, respectively. The 2-year RFS rates for the M0, M1, and M2 groups were 57.8%, 43.7%, and 11.1%, while the 2-year OS rates were 92.9%, 84.7%, and 40.1%, respectively (all p < 0.05). Multivariable analysis demonstrated that M1 and M2 were associated with poorer RFS (HR 1.81, 95% CI:1.17–2.11; HR 3.98, 95% CI:1.91–8.29) and OS (HR 3.57, 95% CI:1.05–13.33; HR 12.22, 95% CI:3.87–38.61). The grading severity of MVI was strongly associated with postoperative oncological outcomes in uHCC patients undergoing hepatectomy following conversion therapy with TKIs and anti-PD-1 antibodies, serving as a valuable tool for guiding postoperative risk stratification.