The role of macroscopic classification in nodular-type hepatocellular carcinoma

Background: Little has been reported on the role of macroscopic classification of hepatocellular carcinoma (HCC). We hypothesized that macroscopic classification of HCC might have a strong correlation with long-term prognosis after hepatectomy. Methods: Four hundred and four patients with a macroscopically nodular type of HCC who underwent a hepatectomy were studied. The patients were divided into three groups: single nodular (SN) group (n = 312); single nodular with extranodular growth (SNEG) group (n = 52); and confluent multinodular (CMN) group (n = 40). Clinicopathological variables were compared among the three groups. The patient survival rate was also compared among the three groups. Finally, a multivariate analysis was performed to clarify the independent significant variables of the long-term prognosis. To confirm the consistency of the results in small-size HCC, the same analyses were made using patients whose tumor size was equal to or less than 3 cm in diameter. Results: The α-fetoprotein value, tumor size, and rate of absolute noncurative operation in the SNEG group were higher than in other groups. The positive rate of both portal vein invasion of cancer cells and intrahepatic metastasis in the SN group was lower than those in other groups. The rate of poorly differentiated histology in the SN group was lower than in the other groups. Patient survival in the SNEG group was worst among the three groups. However, patient survival showed no significant difference between the SN and CMN groups. The multivariate analysis showed that the presence of intrahepatic metastasis, the macroscopic classification of SNEG type, and absolute noncurative operation were independent poor prognostic indicators. The results for patients with small HCCs measuring equal to or less than 3 cm in diameter were quite similar to the results for the other patients. Conclusions: Among the three subtypes of macroscopically nodular type of HCCs, the SNEG type showed higher rates of portal vein invasion of cancer cells, intrahepatic metastasis, and poorly differentiated histology. The patient survival rate in the SNEG type was worst, and the SNEG type was an independent poor prognostic indicator. The macroscopic classification of HCC, especially the SNEG type, helps predict the long-term outcome after hepatectomy.