We conducted a systematic review and meta-analysis of all observational studies to define the safety and efficacy of simultaneous versus delayed resection of the colon and liver. A search for all major databases and relevant journals from inception to April 2012 without restriction on languages or regions was performed. Outcome measures were the primary parameters

of postoperative survival, complication, and mortality, as well as other parameters of blood loss, operative time, and length of hospitalization. The test of heterogeneity was performed with the Q statistic. A total of 2,880 patients were included in the meta-analysis. Long-term oncological pooled estimates of overall survival (hazard ratio [HR]:

0.96; 95% confidence interval [CI]: 0.81-1.14; Palbociclib P = 0.64; I2 = 0) and recurrence-free survival (HR: 1.04; 95% CI: 0.76-1.43; P = 0.79; I2 = 53%) all showed similar outcomes for both Smoothened Agonist molecular weight simultaneous and delayed resections. A lower incidence of postoperative complication was attributed to the simultaneous group as opposed to that in the delayed group (modified relative ratio [RR] = 0.77; 95% CI: 0.67-0.89; P = 0.0002; I2 = 10%), whereas in terms of mortality within the postoperative 60 days no statistical difference was detected (RR = 1.12; 95% CI: 0.61-2.08; P = 0.71; I2 = 32%). Finally, selection criteria were recommended for SCRLM patients suitable for a simultaneous resection. Conclusion: Simultaneous resection is as efficient as a delayed procedure for long-term survival. There is evidence that in SCRLM patients simultaneous resection is an acceptable and safe option with carefully selected conditions. Due to the inherent limitations of the present study, future randomized controlled trials will be useful to confirm this conclusion. (HEPATOLOGY 2013;57:2346–2357) Colorectal cancer (CRC) remains the second leading cause of cancer-related death in Western Europe and North America, and there are more than 940,000 new cases annually and nearly 500,000 deaths each year worldwide.1-3

Up to 50% of patients with CRC might have liver metastases during the course of the disease, and 15% to 20% have synchronous colorectal liver metastases (SCRLM) at the time of diagnosis, whereas an additional 20% to 25% develop Demeclocycline metachronous hepatic tumors.4-7 The presence of liver metastases has an important influence on patient prognosis, and the median survival is 2.3 to 21.3 months for patients in whom the cancer is nonresected.3, 5, 8-10 Furthermore, liver resection has been accepted as the only treatment offering the chance for a cure and long-term survival, with 5-year survival rates of 25% to 60% and 10-year survival rates of 22% to 26% reported in the literature.11-19 However, optimal timing of liver surgery for synchronous metastases remains controversial and continues to evolve.