The Role of Circulating Biomarkers in the Early Detection of Recurrent Colorectal Cancer Following Resection of Liver Metastases

On a global scale, colorectal cancer (CRC) is currently the fourth most commonly diagnosed cancer and despite progress in early diagnosis and treatment has the third highest mortality. Patients with oligometastatic disease to the liver may be suitable for liver resection with a curative intent. A sustained progress in perioperative management and surgical techniques, including staged liver resections, has increased the number of patients who may be offered hepatectomy. It is well recognised that early detection of any tumour, including recurrence, leads to a timely initiation of treatment with improved outcomes. Tumour biomarkers have long been desired in the search for a tool to aid cancer diagnosis, prognosis and follow-up. Currently, the only widely used biomarker for CRC, Carcinoembryonic Antigen (CEA), has multiple limitations, clearly illustrating the need for novel biomarkers. It is therefore unsurprising that much research has focused on identifying such markers with the literature being swamped with new and promising biomarkers. The aim of this study is to review the current status and role of circulating biomarkers in patients post hepatectomy for colorectal cancer metastasis including alternative cancer antigens to CEA, extracellular vesicles, circulating microRNA, circulating tumour cells and circulating tumour DNA.