Colorectal cancer: features and investigation

Abstract

Colorectal cancer (CRC) is very common, affecting >40,000 people a year in the UK. The pathogenesis is mostly sporadic, but hereditary genes and inflammatory bowel disease are well-known causative factors. The symptoms can be very variable, are based on the location of the lesion and tend to be more obscure if they are right sided. Symptoms also overlap with benign conditions so luminal imaging, mainly colonoscopy as the gold standard, is needed. Bowel cancer screening programmes are designed to detect the earlier stages of CRC. Once the diagnosis has been made, staging is undertaken through computed tomography (CT) of the chest, abdomen and pelvis. For rectal cancers, extra characteristics are obtained through magnetic resonance imaging (MRI) of the pelvis to guide potential preoperative oncology treatment. Additional investigations, such as MRI of the liver or CT positron emission tomography, are sometimes advised through multidisciplinary team discussions to further guide treatment plans.