New metastasectomy criteria for peritoneal metastasis of hepatocellular carcinoma -A study of the Japanese Society of Hepato-Biliary-Pancreatic Surgery.

BACKGROUND Peritoneal metastasis of hepatocellular carcinoma (HCC) is rare. We investigated patients who underwent peritoneal metastasectomy in a multicenter study in Japan. METHODS The study included 92 patients with HCC who underwent resection for peritoneal metastasis between January 2007 and December 2013. We investigated background and operative factors, as well as overall and recurrence-free survival rates. Patients were classified according to the extent of peritoneal metastasis using the peritoneal cancer index (PCI) and the completeness of cytoreduction (CC) scores to examine whether peritoneal metastasectomy contributed to survival. RESULTS The mean maximum tumor size was 4.1 cm. Forty patients (43.5%) had multiple peritoneal metastases. Peritoneal metastasectomy and hepatectomy were performed simultaneously in 48 patients (52.2%). Overall, the 5-year survival rate after resection was 36.0%, and the recurrence-free survival rate was 13.0%. Multivariate analysis revealed that a PCI scores of ≤6 + CC scores of 0 was an independent prognostic factor. The 5-year survival rate when this criteria was met was 43%, which was significantly better than that in those who did not meet this criteria (p < 0.001). CONCLUSIONS Peritoneal metastasectomy of HCC appears to contribute to improved survival of patients with a PCI scores of ≤6, without remnant tumors.