Utility of minimal preparation computed tomography colonography in detecting colorectal cancer in elderly and frail patients

Safety and feasibility of colonoscopy in nonagenarians: A systematic review, meta-analysis and meta-regression analysis

AIM

The aim of this work was to evaluate the safety and feasibility of performing colonoscopy in patients aged 90 years or over.

METHOD

In compliance with PRISMA statement standards, a systematic review of studies reporting the outcomes of colonoscopy in patients aged ≥90 years was conducted. A proportional meta-analysis model was constructed to quantify the risk of outcomes and a direct comparison meta-analysis model was constructed to compare outcomes between nonagenarians and patients aged between 50 and 89 years via random-effects models.

RESULTS

Seven studies enrolling 1304 patients (1342 colonoscopies) were included. Analyses showed that complications related to bowel preparation occurred in 0.7% (95% CI 0.1%-1.6%), procedural complications in 0.6% (0.00%-1.7%), 30-day complications in 1.5% (0.6%-2.7%), procedural mortality in 0.3% (0.0%-1.1%) and 30-day mortality in 1.1% (0.3%-2.2%). Adequate bowel preparation and colonoscopy completion were achieved in 81.3% (73.8%-87.9%) and 92.1% (86.7%-96.3%), respectively. No difference was found in bowel preparation-related complications [risk difference (RD) 0.00, p = 0.78], procedural complications (RD 0.00, p = 0.60), 30-day complications (RD 0.01, p = 0.20), procedural mortality (RD 0.00, p = 1.00) or 30-day mortality (RD 0.01, p = 0.34) between nonagenarians and patients aged between 50 and 89 years. The colorectal cancer detection rate was 14.3% (9.8%-19.5%), resulting in therapeutic intervention in 65.9% (54.5%-76.6%).

CONCLUSIONS

Although the evidence is limited to a selected group of nonagenarians, it may be fair to conclude that if a colonoscopy is indicated in a nonagenarian with good performance status (based on initial less-invasive investigations), the level 2 evidence supports its safety and feasibility. Age on its own should not be a reason for failing to offer colonoscopy to a nonagenarian.

Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Feasibility of Simple Oral Preparation Contrast-Enhanced CT Colonography (SOP-CE-CTC) Using Mannitol as a Neutral Oral Contrast Agent

Purpose This article prospectively assesses the feasibility of simple oral preparation contrast-enhanced computed tomography colonography (SOP-CE-CTC) using a large volume of oral 3% mannitol for good colonic distension along with mural and mucosal fold visualization.

Methods A total of 100 patients in whom contrast CT abdomen was requested, recruited as per selection criteria, were advised to take mild oral bowel preparation for two nights, prior to the investigation. Then, after fasting overnight, they were asked to consume 1,500 to 2,000 mL of 3% mannitol solution in about an hour. Thirty minutes after completing the ingestion of oral mannitol, intravenous contrast was injected and SOP-CE-CTC was acquired at 55 seconds. Distension of six segments of the colon was evaluated by assigning scores 1 to 4 for qualitative assessment; and measuring the maximum luminal diameter of the colon, for quantitative assessment. Colonic mucosal and mural visualization were evaluated subjectively. All observations were recorded by two reviewers (with varying levels of experience) independently.

Results On qualitative analysis, the colon showed optimal distension (score 4) in 58 to 89% cases on SOP-CE-CTC. There was agreement between both the reviewers in 89 to 99% cases (weighted kappa 0.820–0.979; p < 0.001). On quantitative analysis, the mean of the maximum colonic diameter ranged between 3.4 and 5.2 cm; and both the reviewers agreed in 89 to 97% cases (weighted kappa 0.777–0.967; p < 0.001). Mural and mucosal fold visualization in the proximal four segments of the colon was excellent (in 90–98%) but in the rectum and sigmoid it was 45 and 66%, respectively; both the reviewers agreed in 100% cases (weighted kappa 1.0 and p < 0.001).

Conclusion Good colonic distension, mural, and mucosal fold visualization can be achieved on SOP-CE-CTC using 1,500 to 2,000 mL of 3% oral mannitol and mild oral bowel preparation agents.

Computed tomography colonography versus colonoscopy for detection of colorectal cancer: a diagnostic performance study

BACKGROUND

Colonoscopy is the reference standard for the detection of colorectal cancer but it is an invasive technique and has the risk of bowel perforation and bleeding. Unlike colonoscopy, sedation is not required in computed tomography colonography and requires additional reassurance endoscopy. The objectives of the study were to compare the diagnostic performance of computed tomography colonography against colonoscopy for a diagnosis of colorectal cancer.

METHODS

Data regarding any polyp ≥10 mm diameter (ø) and < 10 mm ø but suspicious polyps of computed tomography colonography (n = 318), colonoscopy (n = 318), and surgical pathology (n = 77) for symptomatic colorectal cancer patients were collected and analyzed. Lesion ulceration, extramural invasion, and/ or lesion shouldering was considered as a suspicious polyp. Beneficial scores for decision making of curative surgeries were evaluated for each modality. The cost of diagnosis of colorectal cancer was also evaluated.

RESULTS

Either of diagnosis showed polyps ≥10 mm ø in 27 patients and polyps of 50 patients were < 10 mm ø but suspicious. Therefore, a total of 77 patients were subjected to surgery. With respect to surgical pathology, sensitivities for computed tomographic colonography and colonoscopy were 0.961 and 0.831. For detection of ≥10 mm ø polyp, benefit score for computed tomographic colonography and colonoscopy were 0-0.906 diagnostic confidence and 0.035-0.5 diagnostic confidence. For polyps, ≥ 10 mm ø but not too many large polyps, colonoscopy had the risk of underdiagnosis. For < 10 mm ø but suspicious polyps, < 0.6 mm ø and < 2.2 mm ⌀ polyps could not be detected by computed tomographic colonography and colonoscopy, respectively. The computed tomographic colonography had less cost than colonoscopy (1345 ± 135 ¥/ patient vs. 1715 ± 241 ¥/ patient, p < 0.0001) for diagnosis of colorectal cancer.

CONCLUSION

Computed tomographic colonography would be a non-inferior alternative than colonoscopy for a diagnosis of colorectal cancer.

LEVEL OF EVIDENCE

III.