Post-operative colorectal cancer surveillance: preference for optical colonoscopy over computerized tomographic colonography

[Imaging of colorectal cancer: Role of computed tomography colonography]

BACKGROUND

Computed tomography colonography (CTC) is a minimally invasive examination for radiologic imaging of the entire colon and rectum. It has replaced the now obsolete barium enemas and represents an important option to colonoscopy for the detection of colorectal neoplasia.

OBJECTIVES

The aim of this article is to review the current status of CTC for detection of colorectal cancer (CRC) and its precursors.

MATERIALS AND METHODS

Based on an extensive literature research, the current role of CTC in colorectal cancer imaging is summarized. This includes not only CRC detection but also the role of CTC in CRC screening and surveillance.

RESULTS

CTC is a well-developed, minimally invasive examination for the identification of colorectal neoplasia. The diagnostic accuracy for colorectal adenomas and cancer is comparable to that of optical colonoscopy. Missed CRC cases are rare and typically result from perceptual or technical errors. In addition to the detection and characterization of carcinomas, CTC enables the visualization of prestenotic colonic segments and extracolonic structures. This allows for the preoperative detection of synchronous colonic neoplasms that are not endoscopically assessable as well as evaluation of abdominal tumor spread. Due to its ability to detect benign precancerous adenomas with high sensitivity, CTC can be used for opportunistic colorectal cancer screening. In CRC follow-up, CTC may be used to diagnose recurrence if colonoscopy is incomplete or not feasible.

CONCLUSION

CTC is the radiological examination of choice for the detection of colorectal neoplasia. It is typically used in patients where colonoscopy is incomplete, contraindicated or refused. Moreover, CTC serves as a noninvasive option for opportunistic colorectal cancer screening.

Imaging alternatives to colonoscopy: CT colonography and colon capsule. European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline - Update 2020

1: ESGE/ESGAR recommend computed tomographic colonography (CTC) as the radiological examination of choice for the diagnosis of colorectal neoplasia.Strong recommendation, high quality evidence.ESGE/ESGAR do not recommend barium enema in this setting.Strong recommendation, high quality evidence. 2: ESGE/ESGAR recommend CTC, preferably the same or next day, if colonoscopy is incomplete. The timing depends on an interdisciplinary decision including endoscopic and radiological factors.Strong recommendation, low quality evidence.ESGE/ESGAR suggests that, in centers with expertise in and availability of colon capsule endoscopy (CCE), CCE preferably the same or the next day may be considered if colonoscopy is incomplete.Weak recommendation, low quality evidence. 3: When colonoscopy is contraindicated or not possible, ESGE/ESGAR recommend CTC as an acceptable and equally sensitive alternative for patients with alarm symptoms.Strong recommendation, high quality evidence.Because of lack of direct evidence, ESGE/ESGAR do not recommend CCE in this situation.Very low quality evidence.ESGE/ESGAR recommend CTC as an acceptable alternative to colonoscopy for patients with non-alarm symptoms.Strong recommendation, high quality evidence.In centers with availability, ESGE/ESGAR suggests that CCE may be considered in patients with non-alarm symptoms.Weak recommendation, low quality evidence. 4: Where there is no organized fecal immunochemical test (FIT)-based population colorectal screening program, ESGE/ESGAR recommend CTC as an option for colorectal cancer screening, providing the screenee is adequately informed about test characteristics, benefits, and risks, and depending on local service- and patient-related factors.Strong recommendation, high quality evidence.ESGE/ESGAR do not suggest CCE as a first-line screening test for colorectal cancer.Weak recommendation, low quality evidence. 5: ESGE/ESGAR recommend CTC in the case of a positive fecal occult blood test (FOBT) or FIT with incomplete or unfeasible colonoscopy, within organized population screening programs.Strong recommendation, moderate quality evidence.ESGE/ESGAR also suggest the use of CCE in this setting based on availability.Weak recommendation, moderate quality evidence. 6: ESGE/ESGAR suggest CTC with intravenous contrast medium injection for surveillance after curative-intent resection of colorectal cancer only in patients in whom colonoscopy is contraindicated or unfeasibleWeak recommendation, low quality evidence.There is insufficient evidence to recommend CCE in this setting.Very low quality evidence. 7: ESGE/ESGAR suggest CTC in patients with high risk polyps undergoing surveillance after polypectomy only when colonoscopy is unfeasible.Weak recommendation, low quality evidence.There is insufficient evidence to recommend CCE in post-polypectomy surveillance.Very low quality evidence. 8: ESGE/ESGAR recommend against CTC in patients with acute colonic inflammation and in those who have recently undergone colorectal surgery, pending a multidisciplinary evaluation.Strong recommendation, low quality evidence. 9: ESGE/ESGAR recommend referral for endoscopic polypectomy in patients with at least one polyp ≥ 6 mm detected at CTC or CCE.Follow-up CTC may be clinically considered for 6 - 9-mm CTC-detected lesions if patients do not undergo polypectomy because of patient choice, comorbidity, and/or low risk profile for advanced neoplasia.Strong recommendation, moderate quality evidence.

Computed Tomography Colonography Versus Standard Optical Colonoscopy for the Detection of Colorectal Polyp in Patients Who Faced Curative Surgery for Colorectal Cancer: A Diagnostic Performance Study

Data regarding computed tomography colonography, standard optical colonoscopy, and enhanced colonoscopy/histopathology at 1-year after surgery and at 6-month intervals for the next 2 years of 345 patients who faced curative surgery for colorectal cancer were included in this analysis. Computed tomography colonography and standard optical colonoscopy both detected 298 polyps as suspicious. With reference to enhanced colonoscopy/histopathology, sensitivities for the detection of any polyps for computed tomography colonography and standard optical colonoscopy were 0.952 and 0.906, while, accuracies were 0.783 and 0.641, respectively. Computed tomography colonography may be a sensitive and accurate surveillance tool for colorectal cancer patients.