Worse Prognosis of Patients With Hepatocellular Carcinoma and Portal Vein Invasion Underestimated by Imaging

ABSTRACT Background Portal vein invasion is closely linked to poor prognosis in hepatocellular carcinoma (HCC). However, no study has directly compared preoperative imaging with postoperative histopathological diagnoses of portal vein invasion. This study evaluated the prognostic impact of underdiagnosed portal vein invasion in patients undergoing hepatectomy. Methods We retrospectively reviewed 1328 patients who underwent initial hepatectomy for HCC from January 2000 to December 2020. Portal vein invasion was classified as Image‐Vp0–4 based on preoperative imaging and vp0–4 based on postoperative pathology. Underdiagnosis was defined as IVp < vp; otherwise, IVp ≥ vp. Gross invasion was defined as vp2–4, and non‐gross invasion as vp0/1. Results Pathological staging stratified overall survival (OS) more clearly than imaging (median OS: vp0 = 7.9 years; vp1 = 5.6; vp2 = 2.5; vp3 = 1.6; vp4 = 0.5), while Image‐Vp showed less consistent trends (Vp0–4 = 7.9; 7.6; 9.5; 1.6; 0.5 years). Underdiagnosis occurred most frequently in Image‐Vp0 and vp1 cases (16.7%). Patients with IVp < vp had significantly worse OS than those with IVp ≥ vp (5.6 vs. 7.9 years, p < 0.001). Among vp0/1 patients, OS was significantly shorter in underdiagnosed cases (5.8 vs. 7.9 years, p < 0.001), whereas in vp2–4 cases, underdiagnosis had no significant effect (3.9 vs. 1.6 years, p = 0.317). Conclusions Underdiagnosis of vp1 was associated with significantly reduced survival in HCC patients, despite negative imaging findings. These results highlight the critical role of postoperative histopathology in accurately assessing portal vein invasion.