Risk factors for colonic perforation after screening computed tomographic colonography: a multicentre analysis and review of the literature

The potential of imaging techniques as a screening tool for colorectal cancer: a cost-effectiveness analysis

OBJECTIVE

Imaging may be promising for colorectal cancer (CRC) screening, since it has test characteristics comparable with colonoscopy but is less invasive. We aimed to assess the potential of CT colonography (CTC) and MR colonography (MRC) in terms of (cost-effectiveness) using the Adenoma and Serrated pathway to Colorectal CAncer model.

METHODS

We compared several CTC and MRC strategies with 5- or 10-yearly screening intervals with no screening, 10-yearly colonoscopy screening and biennial faecal immunochemical test (FIT) screening. We assumed trial-based participation rates in the base-case analyses and varied the rates in sensitivity analyses. Incremental lifetime costs and health effects were estimated from a healthcare perspective.

RESULTS

The health gain of CTC and MRC was similar and ranged from 0.031 to 0.048 life-year gained compared with no screening, for 2-5 screening rounds. Lifetime costs per person for MRC strategies were €60-110 higher than those for CTC strategies with an equal number of screening rounds. All imaging-based strategies were cost-effective compared with no screening. FIT screening was the dominant screening strategy, leading to most LYG and highest cost-savings. Compared with three rounds of colonoscopy screening, CTC with five rounds was found to be cost-effective in an incremental analysis of imaging strategies. Assumptions on screening participation have a major influence on the ordering of strategies in terms of costs and effects.

CONCLUSION

CTC and MRC have potential for CRC screening, compared with no screening and compared with three rounds of 10-yearly colonoscopy screening. When taking FIT screening as the reference, imaging is not cost-effective. Participation is an important driver of effectiveness and cost estimates.

ADVANCES IN KNOWLEDGE

This is the first study to assess the cost-effectiveness of MRC screening for CRC.

Case Report: Rectal perforation during CT colonography

Introduction

Computer tomography colonoscopy (CTC) is an increasingly prevalent procedure for the investigation of colorectal symptoms, or as a component of colorectal cancer screening.  It is considered a low risk procedure, however colonic perforation is a recognized significant complication.

Case Report

We report the case of an 81-year-old female patient who underwent CTC after failed optical colonoscopy as part of routine colorectal cancer screening.  Perforation of the rectum with surrounding pararectal air was confirmed on CTC.  The patient had minimal symptoms and was treated successful non-operatively with bowel rest and antibiotics.

Conclusion

Perforation sustained during CTC is an uncommon complication.  The incidence of perforation during CTC is still lower than that during optical colonoscopy.  In the absence of significant abdominal signs and symptoms, this rare complication may be successfully managed non-operatively.

The safety of same-day CT colonography following incomplete colonoscopy with polypectomy

BACKGROUND

Concerns about the risk of bowel perforation for same-day computed tomography colonography (CTC) following an incomplete colonoscopy with polypectomy may lead to unnecessarily postponing the CTC.

OBJECTIVE

The objective of this article is to describe the complications including colon perforations associated with same-day CTC in a cohort who had polypectomies but an incomplete colonoscopy.

DESIGN

We conducted a retrospective study.

SETTING

Our study took place in a single, tertiary referral center.

PATIENTS

We studied consecutive patients who had CTC the same day as an incomplete colonoscopy with polypectomy.

INTERVENTIONS

Interventions included optical colonoscopy (OC), endoscopic polypectomies, and same-day CTC.

MAIN OUTCOME MEASUREMENTS

Our main outcome measurements included perforation rate with long-term follow-up.

RESULTS

A total of 3% of patients undergoing colonoscopy from January 2008 to December 2012 had same-day CTC following incomplete OC, and 72 polypectomies were performed in 34 (or 17%) of these patients. Incomplete colonoscopies were due to colon tortuosity and looping (25), severe angulations (five), colon mass (two), colon stenosis (one), bradycardia (one). Fifty-three percent of the OCs were screening for colon neoplasia, 29% diagnostic and 18% were surveillance of colon polyps. Most polyps were ≤ 5 mm, and found in the left colon. There were no reported complications or perforations associated with same-day CTCs during short- and long-term follow-up.

LIMITATIONS

Limitations of our analysis included retrospective single-center design, small number of patients for the occurrence, referral to same-day CTC was not standardized, inability to establish safety of CTC for specific scenarios such as after complex polypectomies, strictures, or advanced IBD.

CONCLUSIONS

Radiologists' apprehension to perform a CTC the same day as an incomplete colonoscopy following polypectomies because of perceived risk of perforation may be unfounded. More data are needed to determine the safety of same-day CTC in patients with high-risk findings during colonoscopy such as a stricture, severe IBD, and after complex polypectomies.

Iatrogenic Colonic Perforation due to Computed Tomographic Colonography

Although the complications of computed tomographic colonography (CTC) are very rare, CTC is associated with potential risk of colonic perforation. In the present report we describe two cases of colonic perforation secondary to CTC. In the first case with ascending colonic carcinoma, insertion of a rigid double-balloon catheter caused direct rectal wall perforation. In the second case with obstructive colonic carcinoma, pneumoperitoneum developed due to automated carbon dioxide insufflation. Both patients were asymptomatic after examination and recovered without any complications. Based on the findings of the current cases, we recommend that a soft-tip catheter be used for CTC, and suggest that colonic perforation can occur even with automatic insufflation, depending on patient characteristics.

Non- or full-laxative CT colonography vs. endoscopic tests for colorectal cancer screening: a randomised survey comparing public perceptions and intentions to undergo testing

Objectives

Compare public perceptions and intentions to undergo colorectal cancer screening tests following detailed information regarding CT colonography (CTC; after non-laxative preparation or full-laxative preparation), optical colonoscopy (OC) or flexible sigmoidoscopy (FS).

Methods

A total of 3,100 invitees approaching screening age (45-54 years) were randomly allocated to receive detailed information on a single test and asked to return a questionnaire. Outcomes included perceptions of preparation and test tolerability, health benefits, sensitivity and specificity, and intention to undergo the test.

Results

Six hundred three invitees responded with valid questionnaire data. Non-laxative preparation was rated more positively than enema or full-laxative preparations [effect size (r) = 0.13 to 0.54; p < 0.0005 to 0.036]; both forms of CTC and FS were rated more positively than OC in terms of test experience (r = 0.26 to 0.28; all p-values < 0.0005). Perceptions of health benefits, sensitivity and specificity (p = 0.250 to 0.901), and intention to undergo the test (p = 0.213) did not differ between tests (n = 144-155 for each test).

Conclusions

Despite non-laxative CTC being rated more favourably, this study did not find evidence that offering it would lead to substantially higher uptake than full-laxative CTC or other methods. However, this study was limited by a lower than anticipated response rate.

Key Points

• Improving uptake of colorectal cancer screening tests could improve health benefits

• Potential invitees rate CTC and flexible sigmoidoscopy more positively than colonoscopy

• Non-laxative bowel preparation is rated better than enema or full-laxative preparations

• These positive perceptions alone may not be sufficient to improve uptake

• Health benefits and accuracy are rated similarly for preventative screening tests

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-014-3187-9) contains supplementary material, which is available to authorized users.

Perforation rate in CT colonography: a systematic review of the literature and meta-analysis

PURPOSE

The primary aim was to assess the perforation rate of CTC; the secondary aim was to identify potential clinical/technical predictors of this complication.

METHODS

Methods for analysis were based on PRISMA (preferred reporting items for systematic reviews and meta-analyses). From the selected studies, the rate of CTC perforation and patient/technical characteristics potentially associated with this event were extracted. Forest plots showing individual and pooled estimates of the perforation rate were obtained for all analyses. I(2) was used to evaluate heterogeneity between studies.

RESULTS

Eleven articles out of the 187 initially identified were selected for the analysis (103,399 patients). There were 29,048 (28%) asymptomatic individuals and 30,773 (30%) symptomatic patients; this characteristic was not reported in the remaining subjects (42%). Colon distension was obtained manually in 69,222 (67%) and using an automated carbon dioxide insufflator in 26,479 (26%) patients; in the remaining 7% of patients, this information was missing. Twenty-eight colonic perforations were reported, with the CTC perforation rate estimated to be 0.04% (95% CI. 0.00-0.10), 19-fold higher in symptomatic than in screening subjects (OR: 19.2, CI 3.3-108 and P = 0.001). The surgical rate was 0.008%. No CTC-related deaths were reported.

CONCLUSIONS

The perforation rate in CTC is very low, particularly considering asymptomatic individuals.

KEY POINTS

• This is the first meta-analysis on this topic, based on 100,000 patients. • The CTC-related colorectal perforation rate is 0.04%, 0.02% in asymptomatic subjects. • The CTC-induced surgery rate is 0.008% (1:12,500). • The perforation rate in CTC is low, particularly in average-risk, asymptomatic individuals.

CT colonography in the diagnosis and management of colorectal cancer: Emphasis on pre- and post-surgical evaluation

This article addresses the use of computed tomographic colonography (CTC) for the diagnosis and management of colorectal cancer, focusing on presurgical evaluation of the colon proximal to an occlusive cancer and surveillance after cancer resection surgery. The key evidences accumulated in the literature and future work needed are summarized. CTC is a technically robust and the most practical method to evaluate the colon proximal to an occlusive cancer, which prevents colonoscopic examination past the occlusion, either before or after metallic stent placement. The high sensitivity of CTC for detecting cancers and advanced adenomas in the proximal colon can help prevent additional surgical procedures in patients showing negative results. However, the accuracy of CTC for distinguishing intramural cancers from adenomas is low, and the technique is limited in guiding management when a medium-sized lesion that do not show invasive features such as pericolic extension or nodal metastasis is found in the proximal colon. A maximal diameter ≥ 15 mm has been proposed as a criterion for surgical removal of proximal lesions. However, this needs to be verified in a larger cohort. In addition, the influence of presurgical CTC results on the current post-cancer resection colonic surveillance timeline remains to be determined. CTC can be readily added to the routine abdominopelvic CT in the form of contrast-enhanced CTC, which can serve as an effective stand-alone tool for post-cancer resection surveillance of both the colorectum and extracolonic organs. Although the accuracy of CTC has been demonstrated, its role in the current colonoscopy-based postoperative colonic surveillance protocols remains to be determined. Readers of CTC also need to be knowledgeable on the colonic lesions that are unique to the postoperative colon.

Computed tomography colonography technique: the role of intracolonic gas volume

Introduction. Poor distention decreases the sensitivity and specificity of CTC. The total volume of gas administered will vary according to many factors. We aim to determine the relationship between the volume of retained gas at the time of image acquisition and colonic distention and specifically the presence of collapsed bowel segments at CTC. Materials and Methods. All patients who underwent CTC over a 12-month period at a single institution were included in the study. Colonic luminal distention was objectively scored by 2 radiologists using an established 4-point scale. Quantitative analysis of the volume of retained gas at the time of image acquisition was conducted using the threshold 3D region growing function of OsiriX. Results. 108 patients were included for volumetric analysis. Mean retained gas volume was 3.3 L. 35% (38/108) of patients had at least one collapsed colonic segment. Significantly lower gas volumes were observed in the patients with collapsed colonic segments when compared with those with fully distended colons 2.6 L versus 3.5 L (P = 0.031). Retained volumes were significantly higher for the 78% of patients with ileocecal reflux at 3.4 L versus 2.6 L without ileocecal reflux (P = 0.014). Conclusion. Estimation of intraluminal gas volume at CTC is feasible using image segmentation and thresholding tools. An average of 3.5 L of retained gas was found in diagnostically adequate CTC studies with significantly lower mean gas volume observed in patients with collapsed colonic segments.

Adverse events of computed tomography colonography: an Italian National Survey

AIM

To retrospectively study the frequency and magnitude of complications associated with computed tomography (CT) colonography in clinical practice.

METHODS

A questionnaire on complications of CT colonography was sent to Italian public radiology departments identified as practicing CT colonography with a reasonable level of training. The frequency of complications and possible risk factors were retrospectively determined. Responses were collated and row frequencies determined. A multivariate analysis of the factors causing adverse events was also performed.

RESULTS

40,121 examinations were performed in13 centers during the study period. No deaths were reported. Bowel perforations occurred in 0.02% (7 exams). All perforations were asymptomatic and occurred in patients undergoing manual insufflation. Five perforations (71%) occurred in procedures performed following a recent colonoscopy. There was no significant difference between perforations associated with rectal balloon (0.017%) and those that were not (0.02%). Complications related to vasovagal reaction (either with or without spasmolytic) occurred in 0.16% (63 exams). All vasovagal reactions resolved in less than 3h, without any sequelae.

CONCLUSIONS

Perforation rate at CT colonography in Italy is comparable with elsewhere in the world, occurring regardless of the experience of radiology centers. Although the risk is very small, it may not be negligible when compared with the risk of diagnostic colonoscopy.

Complications of CT colonography: a review

Since its inception, one of the main advantages of computed tomography colonography (CTC) over colonoscopy has been its assumed superior safety profile. However CTC is not without complication and adverse events are well described. Although the risks of insufflation, bowel preparation, contrast media and radiation dose are very small, they are not insignificant. This review discusses the potential hazards and complications associated with the technique, and discuss precautions, which may lessen the risk of occurrence.

Evidence review and status update on computed tomography colonography

Computed tomographic (CT) colonography is being implemented increasingly in the USA and Europe, and in many centers it has become the radiological technique of choice for imaging the whole colorectum. Although high diagnostic accuracy has been demonstrated in both screening and symptomatic populations, controversy persists regarding implementation, who should interpret the examination, and its cost effectiveness, particularly in the context of primary colorectal cancer screening. Published research in recent years has demonstrated efficacy in a wide range of patient groups, striking technical improvements, and high levels of patient acceptability. New developments continue in the fields of computer aided detection, digital cleansing, and integration into positron emission tomography. The purpose of this review is to bring the reader up-to-date with the latest developments in CT colonography, in particular, those of the last year.