Alcohol Use and the Risk of Colorectal Liver Metastasis: A Systematic Mapping Review

SIMPLE SUMMARY: Colorectal cancer (CRC) is the third most diagnosed cancer worldwide and the second leading cause of death in the United States. Many deaths associated with CRC are due to the metastatic spread of colon tumors to the liver. Drinking alcohol has been associated with liver diseases and an increased risk of developing colon cancer. However, it is not understood whether alcohol consumption and related liver damage associates with liver metastasis and worse outcomes in CRC patients. The objective of this study was to conduct a systematic mapping review of the literature to identify gaps in research investigating alcohol use and the risk of colorectal liver metastasis (CRLM). The review identified 14 publications in the last decade that evaluated alcohol use, the risk of CRLM, and contributing mechanisms involved in promoting metastasis in the alcohol-injured liver. The number of studies identified demonstrates the limited focus in current research evaluating the consequences of alcohol consumption in metastatic disease and the health of CRC patients. Overall, significant gaps in this area of research have been identified demonstrating the need for a better understanding of major worldwide healthcare issues related to alcohol use and CRC outcomes. ABSTRACT: The consumption of alcohol has long been associated with the development of liver disease as well as cancers including colorectal cancer (CRC). Leading healthcare concerns include the prevalent use of alcohol and the high burden of CRC mortality. Many CRC deaths are attributed to the development of colorectal liver metastasis (CRLM) as the liver is the foremost site of CRC spread. However, an association has not been defined for the role of alcohol intake and related liver injury with the development of CRLM. Here, a mapping review of recent research was undertaken to evaluate the relationship between alcohol consumption and the risk of CRLM. The literature search revealed 14 articles meeting the inclusion criteria that included patient database analyses and preclinical studies. Most of the human data analyses found alcohol use independently associates with worse CRC outcomes. The preclinical evaluations identified several pathways involved in the alcohol-mediated promotion of CRLM burden and CRC cell metastatic behavior. The limited number of studies identified exposes a significant need for more prospective analyses to define the role of alcohol intake and advanced CRC as well as the translation of preclinical research to fully characterize targetable mechanisms for the generation of new therapeutic options.