Simultaneous Versus Delayed Resection For Synchronous Colorectal Metastases: A Meta-analysis

Introduction: For patient with synchronous colorectal liver metastases, the classical surgical approach is a delayed resection. However more and more surgeon had resected simultaneously colorectal lesions and liver metastases. There is no clear consensus on the optimal timing of surgical resection for synchronous colorectal liver metastases. This aim of the study was to use the systematic review and meta-analysis to analysis the difference of the short-term and long-term outcomes of simultaneous resection and staged resection for synchronous colorectal liver metastases.Method:Systematic review and meta-analysis of studies comparing the short-term and long-term outcomes in patients with synchronous colorectal liver metastases undergoing simultaneous resections versus delayed resections. These included studies were published from 1990 to 2015 in Pub Med and Embase. Pooled odds ratios(OR) or weighted mean differences(WMD) with 95% confidence intervals(95% CI) and hazard ratios were used to analysis parameters, such as overall and disease free survival, mortality, morbidity, duration of hospital stay, duration of surgery and intra-operative blood loss.Result: There were twenty non-randomized studies included, these studies included a total of 3741 patients: 1541(41.2%) had simultaneous resections and 2200(58.8%) had delayed resections. In the delayed resection group versus the simultaneous resection group, the distribution(P < 0.01), size of liver metastases(P < 0.001) and the proportion of major liver resections(P < 0.001) was higher. The overall survival(HR 0.93, 95%CI [0.78,1.11], P=0.40, the disease free survival(HR 0.93,95%CI [0.74,1.17],p=0.52), the mortality(OR 1.30, 95%CI [0.76,2.22], P=0.34) was similar between simultaneous resection and staged resection, and the intra-operative blood loss in the simultaneous resection group did not statistically differ with that in the delayed resection group. Duration of hospital stay(WMD-4.28,95%CI [-5.87,-2.69],P<0.00001) was significantly reduced and morbidity(OR 0.75, 95%CI [0.63,0.89], P=0.0007) was statistically lower in simultaneous resections.Conclusion: As a treatment for synchronous colorectal liver metastases, simultaneous resections are safe and efficient. Simultaneous resection of the primary colorectal tumor and liver metastases does not increase morbidity and mortality rates and offers survival rates similar to staged resection. So delayed resections had a better outcome for older patients with a greater metastatic burden.