Optimal imaging staging of rectal cancer

A patient diagnosed with rectal cancer is managed by a multidisciplinary team in which the radiologist nowadays participates as a full sparring partner. His/her imaging findings can influence the treatment decision-making. The local staging work-up consists of endorectal ultrasound and/or magnetic resonance imaging (MRI). The distant staging work-up depends on the local policy but often consists of ultrasound or computed tomography (CT) of the liver and chest X-ray or chest CT. While previously all patients underwent a standardised resection, nowadays there is evidence that imaging can identify the high risk patients with locally advanced rectal cancer whose tumour is threatening or invading the mesorectal fascia and needs preoperative treatment. This article discusses the role of the different imaging modalities for local staging and restaging of rectal cancer and their accuracies for identifying the risk factors for local recurrence and for assessing response to preoperative chemoradiotherapy. The chapter ends with future perspectives in rectal cancer imaging.