Abstract
As for resection for colorectal liver metastasis (CRLM), securing an adequate surgical margin is important for achieving a better prognosis. However, it is often difficult to achieve adequate margins for the resection of CRLM. So the current survival impact of sub-centi/millimeter surgical margins in hepatectomy for CRLM should be evaluated. In the current era of multidisciplinary treatment options, this review focused on the prognostic impact of a sub-centi/millimeter surgical margin width in hepatectomy for CRLM. We systematically reviewed retrospective studies that clearly described the surgical margin width for hepatectomy for CRLM. We selected studies conducted since 2000 that involved patients diagnosed as having CRLM. We focused on studies that investigated not only surgical margins, but also microscopic surgical curability such as R0 (microscopically complete resection) or R1 (microscopically incomplete resection), which clearly describe their definitions. Based on our literature review, 1, 2, or 5 mm was considered the minimum surgical margin width for hepatectomy for CRLM. Although a surgical margin width of 1 mm is acceptable for hepatectomy for CRLM, submillimeter margins, which are defined as R1 in many reports, are only acceptable for limited patients such as those who have undergone preoperative chemotherapy. Zero-mm margins are also acceptable in limited patients such as those who show a good response to preoperative chemotherapy. New chemotherapy agents have been reported to reduce the prognostic impact of a narrow surgical margin width. The incidence of margin recurrence, which is a major concern regarding R1 resection of CRLM, is about 20-30% according to the majority of earlier reports. As evaluations of the actual prognostic impact of the surgical margin remain difficult, further study is warranted.