Screening Conventional colonoscopy

Akerkar GA, Yee J, Hung R et al (2001) Patient experience and preferences toward colon cancer screening a comparison of virtual colonoscopy and conventional colonoscopy. Gastrointest Endosc 54 310-315... 

Edwards JT, Mendelson RM, Fritschi L, Foster NM, Wood C, Murray D, Forbes GM (2004) Colorectal neoplasia screening with CT colonography in average-risk asymptomatic patients community-based study. Radiology 230 459-464 Fenlon HM, Nunes DP, Schroy PC et al. (1999) A comparison of virtual colonoscopy and conventional colonoscopy for the detection of colorectal polyps. N Engl J Med 341 1496-1503... 

Pickhardt PJ, Choi JR, Hwang 1 et al. (2003) CT virtual colonoscopy to screen for colorectal neosplasia in asymptomatic adults. N Engl J Med 349 2189-2198 Royster AP, Fenlon HM, Clarke PD et al. (1997) CT colonoscopy of colorectal neoplasms two-dimensional and three-dimensional virtual-reality techniques with colonoscopic coreelation. AJR 169 1237-1242 Svensson MH, Svensson E, Lasson A et al. (2002) Patient acceptance of CT colongraphy and conventional colonoscopy prospective comparative study in patients with or suspected of having colorectal disease. Radiology 222 337-345... 

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. 

A landmark multicenter study published by Pickhardt et al. compared CT colonography and conventional colonoscopy in asymptomatic average-risk patient population. As a screening study, comparable adenoma and colorectal cancer detection rates were reported (Pickhardt et al. 2003). In... 

Several studies have shown that patients acceptance of CTC is greater than conventional colonoscopy or double contrast barium enema (Taylor et al. 2003). Development of minimal bowel prep or prep-less CTC through fecal tagging and electronic cleansing appears to be within reach, thus making a truly prep-less colorectal screening test an attractive possibility (Lefere et al. 2002). 

The indications for diagnostic CTC closely follow those for conventional colonoscopy (Rankin 1987). Rectal bleeding, heme positive stool, anemia and constipation are just a few examples. Indications for screening and diagnostic CTC are summarized in Table 2.1. 

Virtual colonoscopy, now ten years old, has made substantial progress in the detection of adenomas and colorectal cancer. Recent studies report comparable sensitivities and specificities to conventional colonoscopy for polyps 10 mm or larger on a per polyp basis. CTC is currently approved by Medicare as a diagnostic study in patients with positive symptoms and after failed colonoscopy. Work continues to approve CTC as a colorectal cancer screening exam. Many experts believe CTC is also ready to be adopted into the colorectal screening algorithm. 

Pickhardt PJ, Choi JR, Hwang I et al. (2003) Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults. NEJM 349 2191-2200 Ristvedt S, McFarland E, Weinstock L et al. (2003) Patient preferences for CT colonography, conventional colonoscopy, and bowel preparation. Am J Gastroenterol 98 578-585 Rockey DC, Paulson EK, Niedzwiecki D et al. (2005) Analysis of air contrast barium enema, computed tomographic colonography, and colonoscopy prospective comparison. Lancet 365 305-311... 

A major requisite, prior to the use of CTC as a screening tool, is to achieve an accuracy level comparative to that of conventional colonoscopy. Until... 

Yet, there is low public acceptability of screening for colorectal cancer by colonoscopy, and a higher rate of patient compliance can be expected with CT colonoscopy (Gluecker et aL 2003), although the patient must undergo a colonic preparation, as with double-contrast barium enema or colonoscopy. Besides, if polyps or tumors are diagnosed by CT, conventional colonoscopy is required to verify the diagnosis, to obtain a biopsy sample, and to remove them. 

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