Indications for conversion hepatectomy for initially unresectable colorectal cancer with liver metastasis.

Purpose: Selected patients with initially unresectable colorectal cancer (CRC) and liver metastases undergo conversion surgery after appropriate chemotherapy. The prognosis of these patients is good, with some even cured of the disease. This retrospective, single-institution study analyzes the clinical importance of patient characteristics on the outcomes of conversion hepatectomy.

Methods: We evaluated 229 consecutive patients with initially unresectable CRC and liver metastasis, who underwent systemic chemotherapy. The patients were assigned to groups depending on conversion hepatectomy.

Results: Conversion hepatectomy was performed in 30 patients (13.1%). The proportion of patients with extrahepatic metastasis was significantly lower in the conversion group than in the unresectable group (30.0 vs. 66.8%; P < 0.01). The rate of left-sided primary colorectal tumors was significantly higher in the conversion group than in the unresectable group (96.7 vs. 65.8%; P < 0.01). Multivariate analyses identified that left-sided tumors, no extrahepatic metastasis, H1 or H2 grade CLM, and treatment with molecular-targeted agents were associated with conversion hepatectomy (odds ratios: 16.314, 4.216, 7.631, and 4.070; P < 0.01). Overall survival was significantly longer in the conversion group than in the unresectable group (MST: 50.0 versus 14.7 months; P < 0.01).

Conclusion: Left-sided primary tumors, absence of extrahepatic metastases, H1 or H2 grade, and use of molecular-targeted agents were associated with successful conversion hepatectomy; thus, patients with these characteristics may be candidates for conversion therapy.