Nonanatomical resection is comparable with anatomical resection in solitary hepatocellular carcinoma <5 cm in the right posterior section

Anatomical resection (AR) is superior to nonanatomical resection (NAR) in theory, but the actual clinical benefit of AR for hepatocellular carcinoma (HCC) is controversial due to the substantial heterogeneity of HCC. Here, we retrospectively compared AR and NAR outcomes for solitary hepatocellular carcinoma (HCC) <5 cm in the right posterior section (RPS) and investigated the risk factors for HCC recurrence and liver-related mortality. The study included 99 consecutive patients who underwent curative surgical resection of an HCC in the RPS (S6 and S7) between January 2003 and December 2009. Each patient had a solitary HCC <5 cm and a noncirrhotic liver. The median estimated blood loss during operation and median operative time were significantly worse in the AR group. In addition, the median tumor size and incidence of microvascular invasion were significantly worse in the AR group. The 1-, 3-, and 5-year disease-free survival rates were 74.1%, 66.3%, and 58.2% in the AR group and 84.7%, 64.4%, and 48.2% in the NAR group, respectively (P = 0.172). The corresponding liver-related overall survival rates were 96.3%, 84.7%, and 77.0% in the AR group and 97.2%, 90.1%, and 88.7% in the NAR group, respectively (P = 0.335). NAR was not associated with HCC recurrence or liver-related mortality in multivariate analysis. The outcomes of NAR for a solitary HCC <5 cm in the RPS are comparable to those achieved with AR with respect to long-term liver-related overall survival and disease-free survival.