Is Liver Ultrasound Useful as Part of the Surveillance Strategy following Potentially Curative Colorectal Cancer Resection?

Background: Optimal surveillance monitoring following curative resection of colorectal cancer remains unclear. Guidelines recommend computed tomography (CT)-based imaging for the initial 3 years following surgical intervention due to the high rates of local and distant recurrence. However, there is currently limited supporting evidence for this strategy. Our current follow-up practice is to offer annual interval abdominal ultrasound and abdominal/pelvis CT scans starting at 6 and 12 months with the sequence of radiological follow-up remaining at the discretion of each clinician. We aim to establish the additional diagnostic benefit of abdominal ultrasound to CT scans in colorectal cancer surveillance follow-up. Methods: All patients who underwent colorectal resection with curative intent in our region during a single year were included. Patients were detected from a prospectively collected pathology database and supplemented retrospectively with patient demographics, imaging reports, and mortality data. Results: A total of 243 patients (male n = 135, 55.6%) were included. There was a mortality rate of 31.3% over the study period. Patients who received abdominal ultrasound as their initial imaging modality (n = 64, 26.3%) were significantly older, had less severe disease, and a significantly lower mortality rate when compared to CT -patients (n = 148, 60.9%). All patients with new hepatic disease detected by ultrasound scans had their management discussed in multi-disciplinary team meetings before their next scheduled CT. Conclusion: In an era where cross-sectional imaging of colorectal cancer is commonplace, abdominal ultrasound offers additional benefit to CT as a postoperative imaging adjunct for the detection of hepatic disease recurrence.