Anatomical versus nonanatomical resection of colorectal liver metastases: a meta-analysis

The purpose of the study was to compare anatomical resection (AR) versus nonanatomical resection (NAR) for colorectal liver metastases (CLM) with respect to perioperative and oncological outcomes. Literature search was performed to identify comparative studies reporting outcomes for both AR and NAR for CLM. Pooled odds ratios (OR) and weighted mean differences (WMD with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model. Seven nonrandomized controlled studies matched the selection criteria and reported on 1,662 subjects, of whom 989 underwent AR, and 673 underwent NAR for CLM. Compared with the perioperative results, NAR reduced the operation time (WMD, 0.39; 95% CI, 1.97-79.17) and blood transfusion requirement (OR, 2.98; 95% CI, 1.87-4.74), whereas postoperative morbidity and mortality were similar between the two groups. With respect to oncologic outcomes, there was no significant difference in surgical margins, overall survival and disease-free survival between the two groups. NAR is a safe procedure for CLM and does not compromise oncological outcomes. However, the findings have to be carefully interpreted due to the lower level of evidence.