Endoscopic resection (ER) is increasingly used for curative treatment of large colorectal superficial neoplastic lesions (CSNL). Experts believe that accurate lesion assessment and in vivo diagnosis should guide treatment decisions for such lesions, however in western practice skills in lesion assessment are less robust and patients frequently undergo biopsy sampling and pre-procedure radiological staging investigations as for any suspected colorectal cancer. For large rectal lesions, many consider pelvic MRI obligatory. The value of such investigations in this context is not clear.Methods
All ER of large (≥20 mm) CSNLs referred to a tertiary unit were included. Data was collected from clinical letters, endoscopy and radiology reports from the referring department as well as the lesion assessment, treatment and final histopathology at our institution. Details of the findings of computed tomography (CT) scans, need for subsequent imaging and potential staging of rectal tumours by MRI were recorded.Results
579 CSNLs≥20 mm were treated with ER. 177 patients (31%) had received a staging CT of the thorax, abdomen and pelvis prior to referral. Of 163 rectal tumours, 67 (41%) had received a staging MRI. The findings of the CT scan did not change the management of the CSNL in any patients. Incidental findings were reported in 28 patients (16%). As a result 25 (89%) went on to require further imaging or referral to other clinicians which resulted in treatment for only one patient who required a ureteric stent for an asymptomatic obstructing stone. No MRI was reported as less than T1 and 31 (30%) were reported as at least T2 or greater, of which only 3 had invasive adenocarcinoma: 2 were T1 with minimal submucosal invasion and one was recognised during the ER as having deep invasion but was unfit for surgery. MRIs in 10 patients were reported as N1–2 (positive lymph node metastases), only 3 had proven adenocarcinoma of which only one eventually agreed to surgery: there was a T3N2 adenocarcinoma but surgery was performed more than 3 years after the initial MRI.Conclusions
Traditional staging radiological investigations have no value in the management of either colonic or rectal large CSNL assessed as likely non-invasive using endoscopic assessment. Instead, they are a significant burden on resources, expose patients to unnecessary radiation, are likely to contribute to unfounded increased anxiety for patients and clinicians and lead to a significant number of additional investigations or specialist consultations without meaningful outcome.