Kato Y, et al. – Researchers here analyzed the impact of serosal invasion on the prognosis after curative hepatectomy for hepatocellular carcinoma, which is histologically classified into four groups according to the definition of the Liver Cancer Study Group of Japan – S₀: no tumor invasion of serosa, S₁: tumor invasion of serosa, S₂: tumor invasion of adjacent organs, S₃: tumor rupture with intraperitoneal bleeding. For both disease–specific survival (DSS) and recurrence–free survival (RFS), they identified invasion to adjacent organs and tumor rupture as crucial prognostic factors. Serosal invasion was identified as an independent prognostic factor only for RFS.