Risk Factors for Postoperative Complications Following Resection of Colorectal Liver Metastases and the Impact on Long-Term Survival: A Population-Based National Cohort Study

Background Postoperative complications (POCs) following resection of colorectal liver metastases (CRLM) are common. The objective of this study was to evaluate risk factors for developing complications and their impact on survival considering prognostic factors of the primary tumor, metastatic pattern and treatment in a well-defined national cohort. Methods Patients treated with resection for CRLM that was also radically resected for their primary colorectal cancer (diagnosed in 2009–2013) were identified in Swedish national registers. Liver resections were categorized according to extent of surgery (Category I–IV). Risk factors for developing POCs as well as prognostic impact of POCs were evaluated in multivariable analyses. A subgroup analysis of minor resections was performed to evaluate POCs after laparoscopic surgery. Results POCs were registered for 24% (276/1144) of all patients after CRLM resection. Major resection was a risk factor for POCs in multivariable analysis (IRR 1.76; P = 0.001). Comparing laparoscopic and open resections in the subgroup analysis of small resections, 6% (4/68) in the laparoscopic group developed POCs compared to 18% (51/289) after open resection (IRR 0.32; P = 0.024). POCs were associated with a 27% increased excess mortality rate (EMRR 1.27; P = 0.044). However, primary tumor characteristics, tumor burden in the liver, extrahepatic spread, extent of liver resection and radicality had higher impact on survival. Conclusion Minimal invasive resections were associated with a decreased risk of POCs following resection of CRLM which should be considered in surgical strategy. Postoperative complications were associated with a moderate risk for inferior survival.