There is a consensus that a positive margin is a predictor of disease recurrence after resection in patients with liver metastases from colorectal cancer. However, there is still controversy regarding the depth of tumor-free margins required during surgery. In this regard, Dr. Zaed Z. R. Hamady et al. from St James University Hospital in the United Kingdom conducted a study aimed at examining the effect of surgical margin depth on the rate of postoperative disease recurrence in patients with colorectal cancer liver metastases undergoing radical resection. This study ultimately concluded that a 1-mm tumor-free margin could be considered as a routine standard of care during surgical resection. The results of this study were published in the June 19, 2013, online issue of Annals of Surgery. The study prospectively collected observational data on 2,715 patients with liver metastases from colorectal cancer who had undergone stage I resection at two large hepatobiliary institutions in the United Kingdom. Patients’ tumor-free margin histology results were classified as positive (tumor cells less than 1 mm from the margin) or negative (tumor greater than or equal to 1 mm from the margin). Negative margins were reclassified according to the centimeter level of distance from the tumor. The researchers analyzed predictors of disease-free survival through univariate and multivariate analyses. To reduce the rate of bias, case-by-case analyses were also performed by propensity score matching. The study found that a 1-mm tumor-free margin was sufficient to achieve a 5-year overall disease-free survival rate of 33%. However, deeper negative margins did not increase the disease-free survival advantage. And a propensity-matched analysis found no statistically significant difference in disease-free survival between patients with narrower negative margins and wider clean margins. In addition, no disease-free survival advantage was obtained for patients with primary tumors who achieved clean margins but had other liver disease and positive lymph nodes. Colorectal cancer (CRC) is the fourth most common type of cancer. 50% of patients with CRC develop colorectal cancer liver metastases (CRLM), which are the leading cause of death. Resection of such metastatic lesions is currently the best treatment available, with over 40% of patients achieving a long survival time after treatment. During the last decade, a large number of observational studies have reached different conclusions regarding whether a 1-cm CRLM without tumor margins is the minimal criterion for radical resection. However, it is not always possible to obtain a wide margin depth because the tumor may be present in the vicinity of large vascular structures or because the residual liver may be too small thereby putting the patient at risk of postoperative death due to liver failure. It has been suggested that a microscopic 1-mm tumor-free margin is sufficient to achieve radical resection and is sufficient to achieve a long-term survival benefit comparable to a 1-cm tumor-free margin. This view is supported by other studies. However, many authors have argued that outcomes are worse for patients with tumor-free margins of less than 1 cm, and the debate continues. The results of a recent meta-study support the wider margin view. However, most of the studies in that meta-analysis were small. In addition, the means of resection used varied between centers, and the heterogeneity of the characteristics of the included samples suggests that the relevant studies collected in the meta-analysis limit the validity of the analysis. Given the difficulty of conducting relevant clinical trials, if the number of cohorts is comparable to the number of subjects included in the meta-analysis, the most effective option would be to refute the meta-analysis with a large cohort review.