Can Cross-Sectional Imaging Reliably Determine Pathological Staging of Right-Sided Colon Cancers and Select Patients for More Radical Surgery or Neo-Adjuvant Treatment?

Purpose and research question Cross-sectional imaging with CT scanning is the most commonly performed imaging modality to stage right-sided colon cancers. There is increasing evidence for the use of neo-adjuvant chemotherapy in selected patients and debate about the role of complete mesocolic excision (CME) and central vascular ligation (CVL) in the management of locally advanced colon cancers. Predicted tumour stage and the presence of nodal metastases by CT are often used to select patients for neo-adjuvant chemotherapy and those that may benefit from CME. This study aims to compare predicted radiological T and N staging with final pathological T and N staging in elective patients having potentially curative surgery for right-sided colon cancer. Methods A retrospective analysis was carried out of a prospectively gathered database of all patients who had undergone (true) right hemicolectomy between 02/01/13 and 21/05/20. Sensitivity, specificity, positive predictive value, and negative predictive value for CT scanning with regards to the pathological nodal metastases were calculated and analysed. Results The sensitivity and specificity of radiology staging for predicting nodal status were 76.4% and 65.5% respectively. The positive predictive value of CT staging for correctly identifying nodal metastases was 55.3%, with a negative predictive value of 77.3%. Conclusions This large series adds further evidence that CT, even when reviewed by expert GI radiologists, has limited accuracy at identifying lymph node metastases in colon cancer.