Verification of evidence in surgical treatment for colorectal liver metastasis

The liver is the predominant site of metastasis from colorectal carcinoma. Although surgical treatment has been widely clinically performed for colorectal liver metastasis (CLM), the evidence of its superiority to other non-surgical methods is unclear. Therefore, this review analyzed the evidence supporting surgical treatment for CLM. A MEDLINE search of papers published after 1990 was performed using the key words "colorectal liver metastasis" and "hepatectomy". Eligible papers were analyzed for evidence level, publication year, and study theme. One hundred and thirty-five papers were eligible for review. One hundred and twenty-one of 135 manuscripts showed evidence level 3 or 4. Only 3 papers showed level 1 (randomized controlled trial), all three of these were related to (neo-) adjuvant therapy. The numbers of manuscript have recently increased more than two-fold when the period investigated was divided into 5-year intervals. About one-third of papers were related to prognostic factors. Papers about surgical procedures, surgical results, diagnosis, and (neo-) adjuvant therapy follow after that in numerical order. In conclusion there is no strong evidence supporting the superiority of surgical treatment for CLM over other treatment methods.