Reappraising the T category in hepatocellular carcinoma: Prognostic impact of the type and extent of vascular invasion.

BACKGROUND

Vascular invasion is a major prognostic determinant in hepatocellular carcinoma, yet the impact of its type and extent on recurrence patterns remains unclear. We aimed to clarify the differential effects of portal, hepatic, and bile duct invasion on recurrence and survival after curative resection.

METHODS

We retrospectively analyzed 1,320 patients who underwent curative hepatocellular carcinoma resection (1990-2022). Vascular invasion was classified by type and grade according to the Japanese classification system. Multivariate Cox regression analyses were performed to evaluate overall survival, recurrence-free survival, and 2-year intrahepatic and extrahepatic recurrence-free survival.

RESULTS

Portal vein invasion was stratified according to its extent. Portal vein invasion 1 was associated with early intrahepatic recurrence (P < .001) but not with early extrahepatic recurrence or overall survival. Portal vein invasion 2 and portal vein invasion 3-4 were associated with early intrahepatic recurrence (portal vein invasion 2: P = .004, portal vein invasion 3-4: P < .001) and worse overall survival (portal vein invasion 2: P < .001, portal vein invasion 3-4: P = .024). Hepatic vein invasion demonstrated a distinct pattern: hepatic vein invasion 1 showed a trend toward early extrahepatic recurrence and was associated with early recurrence but not with overall survival. In contrast, hepatic vein invasion 2-3 was significantly associated with early extrahepatic recurrence (P = .005) and worse overall survival (P = .034). Bile duct invasion was not significantly associated with a poor recurrence-free survival or overall survival.

CONCLUSION

Portal vein invasion 2-4 and hepatic vein invasion 2-3 were associated with distinct early recurrence patterns and worse overall survival. These findings underscore the importance of detailed vascular invasion grading for refined risk stratification and may inform tailored postoperative surveillance and adjuvant strategies.