Colonoscopy Surveillance

Rappeport ED, Loft A, Berthelsen AK et al. (2007) Contrast-enhanced FDG-PET/CT vs. SPIO-enhanced MRI vs. FDG-PET vs. CT in patients with liver metastases from colorectal cancer a prospective study with intraoperative confirmation. Acta Radiol 48 369-378 Rex DK, Kahi CJ, Levin B et al. (2006) Guidelines for colonoscopy surveillance after cancer resection a consensus update by the American Cancer Society and US Multi-Society Task Force on colorectal cancer. CA Cancer J Clin 56 160-167... 

Polyps between 6 and 9 mm are defined as intermediate lesions. Most of them are eventually found to be low-grade dysplasia adenomas, less than 1% are found to be harbour invasive carcinomas and 30% are found to be hyperplastic lesions. Thus, surveillance either with conventional or virtual colonoscopy may be a reasonable option in these cases... 

Winawer SJ, Stewart ET, Zauber AG et al (2000) A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group. N Engl J Med 15 342 1766-1772 Winawer SJ, Fletcher RH, Rex D et al (2003) Colorectal screening and surveillance clinical guidelines rationale-update based on new evidence Gastroenterology 124 544-560... 

The indications for CTC closely follow the indications for conventional optical colonoscopy with few exceptions. These indications include screening asymptomatic high- and average-risk patient populations, pre-operative assessment of the colon proximal to an obstructing mass, evaluation of patients with change in bowel habits, surveillance of patients post colorectal cancer surgery, and incomplete or failed colonoscopy. Patients with bleeding diathesis, contraindications to sedation, and frail and elderly patients may also be better suited for CTC than conventional colonoscopy. 

The role of CT colonography has been evaluated specifically in this patient population. Incomplete colonoscopies secondary to post-operative strictures and rigid mesentery have been reported. In 2002, Gollub et al. reported a conventional colonoscopy failure rate of 4%-29% in post-operative or post-radiotherapy patients (Gollub et al. 2002). These patients would undergo a double contrast barium enema for complete evaluation of the colon. As discussed, CTC sensitivity for polyp detection is greater than DCBE and thus makes it a superior surveillance tool in this subset of patients. 

The American Society of Clinical Oncology developed in 1999 a set of guidelines for the surveillance of the post-operative patient with colorectal cancer after thorough review of the literature of common surveillance protocols. Protocols were reviewed on the basis of reduction in morbidity and five-year disease free survival. Monitoring carcino-embryonic antigen (CEA) levels and colonoscopy were found to be the most effective in many protocols, with liver function evaluation, fecal occult blood testing, liver ultrasound and chest X-ray being less effective in overall outcome (Desch et al. 1999). Colonoscopy appears to have the best predictive value for morbidity. A pre-operative or peri-operative evaluation of the entire colon is essential in the surveillance... 

Fukutomi Y, Moriwaki H, Nagase S et al. (2002) Metachronous colon tumors risk factor and rationale for the surveillance colonoscopy after initial polypectomy. J Cancer Res Clin Oncol 128 569-574... 

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