Obesity and colorectal liver metastases: Mechanisms and management.

INTRODUCTION: Colorectal cancer (CRC) is the third commonest malignancy after lung and breast cancer. The most common cause of mortality from CRC is from distant metastases. Obesity is a known risk factor for primary CRC development. However, its role in metastatic disease progression is not fully understood. The article aims to provide an overview of the role of obesity in colorectal liver metastases (CRLM). Furthermore, possible strategies to minimise this effect are discussed. An electronic search of MedLine, EMBASE, CINAHL and google scholar was performed. Relevant articles were included in the article. Obesity causes localised inflammation within the liver microenvironment which may predispose to metastases development. Furthermore, obesity causes systemic inflammation leading to release of protumourigenic growth factors. Several studies demonstrated the effects of lifestyle modification, medications, bariatric surgery and omega-3 fatty acids on steatosis within the context of liver surgery. It is currently unclear whether obesity directly leads to metastatic disease via chronic systemic inflammation or whether obesity induced steatosis provides a fertile microenvironment for metastases deposition. With a global increase in obesity useful strategies to minimise the effects of obesity on the liver include life-style modification, pre-operative dietary regimes and omega-3 fatty acids intake. Pre-operative optimisation of the patient is a key concept. Further randomised control trials are needed to guide management strategies.