Hepatocellular carcinomas and primary liver tumors as predictive factors for postoperative mortality after liver resection: a meta-analysis of more than 35,000 hepatic resections

Liver resection is considered the therapeutic gold standard for primary and metastatic liver neoplasms. The reduction of postoperative complications and mortality has resulted in a more aggressive approach to hepatic malignancies. For the most part, results of liver surgery have been published by highly experienced institutions, but the observations of highly specialized units results may not reflect the current status of hepatic surgery, underestimating mortality and complications. The objective of this study is to evaluate morbidity and mortality as a result of liver resection for primary and metastatic lesions, analyzing a large number of studies with a meta-analytic process taking into account the overdispersion of data. An extensive literature search has been conducted, and 148 papers published between January 2000 and April 2008, including a total of 36,629 patients from both high-volume and low volume institutions, were included in the metaanalysis. A beta binomial model was used to provide a robust estimate of the summary event rate by pooling overdispersion binomial data from different studies. Overall morbidity and mortality after liver surgery were 29.32 per cent and 3.15 per cent, respectively. Significantly higher postoperative mortality was observed after liver resection for hepatocellular carcinomas and primary hepatic tumors. The application of a beta binomial model to correct for overdispersion of liver surgery data showed significantly higher postoperative mortality rates in patients with hepatocellular carcinomas or primary hepatic tumors after liver resection.