Detection Of Large Polyps Research Articles

Computed tomographic colonography compared with colonoscopy or barium enema for diagnosis of colorectal cancer in older symptomatic patients: two multicentre randomised trials with economic evaluation (the SIGGAR trials).

Computed tomographic colonography (CTC) is a relatively new diagnostic test that may be superior to existing alternatives to investigate the large bowel. To compare the diagnostic efficacy, acceptability, safety and cost-effectiveness of CTC with barium enema (BE) or colonoscopy. Parallel randomised trials: BE compared with CTC and colonoscopy compared with CTC (randomisation 2 : 1, respectively). A total of 21 NHS hospitals. Patients aged ≥ 55 years with symptoms suggestive of colorectal cancer (CRC). CTC, BE and colonoscopy. For the trial of CTC compared with BE, the primary outcome was the detection rate of CRC and large polyps (≥ 10 mm), with the proportion of patients referred for additional colonic investigation as a secondary outcome. For the trial of CTC compared with colonoscopy, the primary outcome was the proportion of patients referred for additional colonic investigation, with the detection rate of CRC and large polyps as a secondary outcome. Secondary outcomes for both trials were miss rates for cancer (via registry data), all-cause mortality, serious adverse events, patient acceptability, extracolonic pathology and cost-effectiveness. A total of 8484 patients were registered and 5384 were randomised and analysed (BE trial: 2527 BE, 1277 CTC; colonoscopy trial: 1047 colonoscopy, 533 CTC). Detection rates in the BE trial were 7.3% (93/1277) for CTC, compared with 5.6% (141/2527) for BE (p = 0.0390). The difference was due to better detection of large polyps by CTC (3.6% vs. 2.2%; p = 0.0098), with no significant difference for cancer (3.7% vs. 3.4%; p = 0.66). Significantly more patients having CTC underwent additional investigation (23.5% vs. 18.3%; p = 0.0003). At the 3-year follow-up, the miss rate for CRC was 6.7% for CTC (three missed cancers) and 14.1% for BE (12 missed cancers). Significantly more patients randomised to CTC than to colonoscopy underwent additional investigation (30% vs. 8.2%; p < 0.0001). There was no significant difference in detection rates for cancer or large polyps (10.7% for CTC vs. 11.4% for colonoscopy; p = 0.69), with no difference when cancers (p = 0.94) and large polyps (p = 0.53) were analysed separately. At the 3-year follow-up, the miss rate for cancer was nil for colonoscopy and 3.4% for CTC (one missed cancer). Adverse events were uncommon for all procedures. In 1042 of 1748 (59.6%) CTC examinations, at least one extracolonic finding was reported, and this proportion increased with age (p < 0.0001). A total of 149 patients (8.5%) were subsequently investigated, and extracolonic neoplasia was diagnosed in 79 patients (4.5%) and malignancy in 29 (1.7%). In the short term, CTC was significantly more acceptable to patients than BE or colonoscopy. Total costs for CTC and colonoscopy were finely balanced, but CTC was associated with higher health-care costs than BE. The cost per large polyp or cancer detected was £4235 (95% confidence interval £395 to £9656). CTC is superior to BE for detection of cancers and large polyps in symptomatic patients. CTC and colonoscopy detect a similar proportion of large polyps and cancers and their costs are also similar. CTC precipitates significantly more additional investigations than either BE or colonoscopy, and evidence-based referral criteria are needed. Further work is recommended to clarify the extent to which patients initially referred for colonoscopy or BE undergo subsequent abdominopelvic imaging, for example by computed tomography, which will have a significant impact on health economic estimates. Current Controlled Trials ISRCTN95152621.

Sedation and Polyp Detection

To the Editor, We read with interest the report by Wang et al. [1] examining the relationship between the depth of sedation and the rate of detection for advanced neoplasia during screening colonoscopy. Their analysis was based upon examination of 104,868 colonoscopies entered into the Clinical Outcomes Research Initiative (CORI) database, a repository of endoscopic reports from 72 centers in the United States. A total of 101,367 procedures (96.7%) were classified as moderate sedation cases and 3,501 (3.3%) were designated as deep sedation procedures. A polyp [9 mm served as a surrogate for advanced neoplasia since pathologic data were not available in all cases. The authors concluded that ‘‘increased advanced adenoma detection is associated with the use of deep sedation’’. Upon careful review of these data, we believe that there is insufficient evidence in the study to support this conclusion. The authors dichotomized sedation technique into deep versus moderate without regard for the drug(s) being administered or the individual responsible for administration. We believe that this method of analysis raises more questions than it answers since the implicit assumption underlying their analysis is that deep sedation is synonymous with the administration of propofol by an anesthesia provider, and moderate sedation constitutes use of benzodiazepine-opioid sedation delivered by a nurse-endoscopist team. There is no evidence to support this assumption, however. The authors could have clarified this issue since the CORI database contains a field specifying the type of individual responsible for managing sedation but for uncertain reasons they chose not to utilize this data. In addition, it is widely recognized that sedation with opioids and benzodiazepines targeted to a state of moderate sedation commonly results in deep sedation [2] and that propofol can be titrated to moderate sedation when used in combination with other sedatives [3]. At least 10.5% of all deep sedation cases reported by Wang et al. represented colonoscopies performed by a single three-physician gastroenterology practice that utilized endoscopist-directed propofol during 17 months of the 5 year period studied (Personal communication, Jennifer Holub, Clinical Outcomes Research Initiative; June 3, 2009). These procedures were designated in the CORI database as ‘‘deep sedation’’ screening colonoscopies and were performed without an anesthesia provider. It is unknown how many additional endoscopists, using either propofol or benzodiazepine-opioid sedation, contributed cases to the CORI database that were designated as ‘‘deep sedation’’ procedures. For this reason, we believe that use of the term ‘‘deep sedation’’ as a proxy for anesthesiaassisted propofol sedation mischaracterizes the sedation technique used in this subset of patients. To our knowledge, an increase in detection of large polyps as a result of any intervention combined with a concomitant decrease in detection of polyps overall is unprecedented. Nearly all technical interventions have an impact primarily on detection of small adenomas [4, 5], P. D. Gerstenberger (&) Digestive Health Associates, PC, 2 Burnett Court, Durango, CO 81301, USA e-mail: pgerstenberger@digestivehealth.net