Long-Term Outcomes of Conversion Hepatectomy for Initially Unresectable Colorectal Liver Metastases

Chemotherapy, including molecular targeted agents, for metastatic colorectal cancer has greatly improved recently and offers an increased chance of conversion hepatectomy for patients with initially unresectable liver metastases. However, the long-term outcomes of conversion hepatectomy remain controversial.

We retrospectively assessed a consecutive series of 210 patients with colorectal liver metastases to evaluate the long-term outcomes of patients who underwent conversion hepatectomy and to clarify the predictive factors related to the conversion rate.

Ninety-four cases were initially resectable and underwent primary hepatectomy. Of the 116 patients with initially unresectable liver metastases, 104 patients underwent chemotherapy (systemic or hepatic artery infusion). Twenty-four percent (11/46) of the initially unresectable liver-limited metastases that became resectable after chemotherapy were subsequently treated with conversion hepatectomy; however, there were no cases of conversion among the patients with extrahepatic metastases. The final resection rate of liver metastases was 50 % (105/210), including conversion hepatectomies. The predicted 5-year survival rate in the conversion hepatectomy group was 76 %. The conversion rate was significantly (P < 0.05) higher in patients with liver-limited metastases (24 %), patients with no LN involvement (27 %), the hepatic arterial infusion chemotherapy group (33 %), patients treated with anti-EGFR agents (21 %), and patients with a complete or partial response (33 %).

Twenty-four percent of the patients with initially unresectable liver-limited metastases became resectable after chemotherapy, and the survival rate after conversion hepatectomy was not inferior to that of the primary hepatectomy cases. Chemotherapy regimens with high response rates are needed to achieve a higher conversion rate.