Reappraisal of evidence of microscopic portal vein involvement by hepatocellular carcinoma cells with stratification of tumor size.

Background: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death internationally, it is necessary to reappraise evidences of HCC cells involving the portal vein, especially considering tumor size.

Materials And Methods: Histopathological evidence and dynamic evidences of radiology and cytology from publication were collected and analyzed.

Results: Frequencies of microscopic portal vein involvement (MPVI) and microscopic intrahepatic metastasis (MIM) in resected specimens with single nodule HCC were lower than that of multi nodule HCC, although not significantly. Early HCC (≤1.5 cm) was with extremely low to 0 frequencies of MPVI and MIM. HCC >5 cm showed a tendency of flowing HCC cells into portal vein, which was coincident with significantly high frequency (64.1 %) of MPVI for HCC >5 cm. There were no significant difference of frequencies of MPVI and MIM between groups of tumor ≤2, ≤3, and ≤5 cm.

Conclusions: Single nodule HCC >5 cm needs anatomic resection and the root of portal vein should be firstly ligated because of tendency of flowing HCC cells into portal vein. For single nodule HCC ≤2 cm, there was a risk of about 16.2 % of MPVI, and a risk of about 16.2-26.4 % of MPVI for those single nodule HCC ≤5 cm, however, there was a risk of extremely low to 0 of MPVI for early HCC (≤1.5 cm). Surgeons have to balance liver reserve and risk of MPVI for HCC ≤5 cm before deciding anatomic or nonanatomic resection.