Chemotherapy and Targeted Therapy for Patients with Initially Unresectable Colorectal Liver Metastases, Focusing on Conversion Hepatectomy and Long-Term Survival

Eight years have passed since the introduction of chemotherapy (chemo) and targeted therapy regimens for colorectal liver metastases (CRLM). This study aimed to clarify the effectiveness of chemo and targeted therapy in facilitating conversion hepatectomy and improving long-term survival in Japanese patients with CRLM. A total of 199 patients with CRLM were treated between May 2005 and August 2012. Initial therapies for these patients included straightforward hepatic resection (n = 48; 24 %), induction chemotherapy (n = 148; 74 %), and radiofrequency ablation (n = 3; 2 %). In 56 of 137 patients (40.1 %) with initially unresectable CRLM, 7.5 courses of chemo and targeted therapy downsized and converted tumors to resectable tumors. The 5-year cumulative overall survival (OS) rate and the median survival time were significantly higher for the resectable CRLM than for the unresectable CRLM (54.6 vs. 5.3 % and 77.3 vs. 21.3 months, respectively; P < .0001). Multivariate analysis revealed that conversion hepatectomy (hazard ratio [HR] 0.19; P < .001) and responder to chemo and targeted therapy (HR 0.46; P < .01) were independent prognostic factors for OS. Multivariate analysis also revealed that left-sided colon or rectal cancer (odds ratio [OR] 8.4; P < .05), H1/H2 metastases (OR 7.3; P < .05), no extrahepatic metastases (OR 52.6; P < .001), and responder to chemo and targeted therapy (OR 6.1; P < .05) were significant predictors of conversion hepatectomy. A chemo and targeted therapy can facilitate conversion hepatectomy and allow for an excellent prognosis in patients with initially unresectable CRLM.