Patient experience and preferences toward colon cancer screening: a comparison of virtual colonoscopy and conventional colonoscopy

Acceptance and Preference of Computed Tomographic Colonography and Colonoscopy: Results of a Nationwide Multicenter Comparative Questionnaire Survey in Japan

Objectives

To investigate patient acceptance and preference for computed tomographic colonography (CTC) over colonoscopy.

Methods

Participants were recruited from a nationwide multicenter trial in Japan to assess the accuracy of CTC detection. They were scheduled to undergo colonoscopy after CTC with common bowel preparation on the same day. Some were administered sedative drugs during colonoscopy, depending on the referring clinician and participant's preferences. The participants were requested to complete a questionnaire to evaluate the acceptability of bowel preparation, examinations, and preference for future examinations.

Results

Of the 1,257 enrolled participants, 1,180 (mean age: 60.6 years; women: 43.3%) completed the questionnaire. Sedative drugs were not administered in 687 participants (unsedated colonoscopy group) and were administered intravenously during colonoscopy in 493 participants (sedated colonoscopy group). Before propensity score matching, the mean participants' age, percentages of asymptomatic participants, insufflation of gas during colonoscopy, and number of participants with a history of abdominal/pelvic operation significantly differed between the groups. After propensity score matching, 912 participants from each group were included in the analysis. In the unsedated colonoscopy group, CTC was answered as significantly easier than colonoscopy (p<0.001). Conversely, CTC was significantly more difficult than colonoscopy in the sedated colonoscopy group (p<0.001). In the unsedated colonoscopy group, 48% preferred CTC and 22% preferred colonoscopy for future examinations, whereas in the sedated colonoscopy group, 26% preferred CTC and 38% preferred colonoscopy (p<0.001).

Conclusions

CTC has superior participant acceptability compared with unsedated colonoscopy. However, our study did not observe the advantages of CTC acceptance over sedative colonoscopy.

Colorectal Cancer Screening: Have We Addressed Concerns and Needs of the Target Population?

Despite the recognized benefits of colorectal cancer (CRC) screening, uptake is still suboptimal in many countries. In addressing this issue, one important element that has not received sufficient attention is population preference. Our review provides a comprehensive summary of the up-to-date evidence relative to this topic. Four OVID databases were searched: Ovid MEDLINE® ALL, Biological Abstracts, CAB Abstracts, and Global Health. Among the 742 articles generated, 154 full texts were selected for a more thorough evaluation based on predefined inclusion criteria. Finally, 83 studies were included in our review. The general population preferred either colonoscopy as the most accurate test, or fecal occult blood test (FOBT) as the least invasive for CRC screening. The emerging blood test (SEPT9) and capsule colonoscopy (nanopill), with the potential to overcome the pitfalls of the available techniques, were also favored. Gender, age, race, screening experience, education and beliefs, the perceived risk of CRC, insurance, and health status influence one’s test preference. To improve uptake, CRC screening programs should consider offering test alternatives and tailoring the content and delivery of screening information to the public’s preferences. Other logistical measures in terms of the types of bowel preparation, gender of endoscopist, stool collection device, and reward for participants can also be useful.

Preference and Experience of Colonic Examination for Participants Presenting to Hospitals with a Positive Fecal Immunochemical Test Result

PURPOSE

Patients who test positive on the fecal immunochemical test (FIT) for colorectal cancer (CRC) are referred for colonoscopy for further diagnostic evaluation. Colonoscopy is not a perfect method and may be a challenge for some FIT-positive patients. Computed tomographic colonography (CTC) is an alternative method that is less invasive and allows examination of the whole colon. The study objective was to evaluate the preference of FIT-positive patients for either colonoscopy or CTC for CRC examination.

PATIENTS AND METHODS

Individuals older than 40 years with a positive FIT test at eight Japanese hospitals between December 2012 and July 2015 were invited to participate. Participants were given detailed information regarding colonoscopy and CTC before deciding on either examination. They completed questionnaires before the procedure regarding their preference and after the procedure regarding their experience.

RESULTS

The pre- and post-questionnaires of 846 and 834 participants, respectively, were analyzed. Participants preferred colonoscopy over CTC (colonoscopy, 72%; CTC, 28%). The possibility of obtaining biopsy samples and removing colorectal polyps during the procedure was the main reason for colonoscopy selection. Patients selected CTC to reduce discomfort but reported that CTC bowel preparation was more burdensome than colonoscopy bowel preparation. The overall experience of the examination did not differ between the groups.

CONCLUSION

Colonoscopy is the standard examination for FIT-positive patients. However, when given a choice, almost one-third of participants chose CTC because they thought it would be a more "comfortable" examination. Clinicians should therefore be aware of patients' potential preference for noninvasive colorectal examinations.

Return to bowel screening after a false-positive faecal immunochemical test in BowelScreen (the National Bowel Screening Programme in Ireland)

Objective

Little research exists on what predicts individual return to screening after a false-positive faecal immunochemical test in a population bowel screening programme. We aimed to quantify the impact of false-positive faecal immunochemical test in the first round of screening on re-attendance in BowelScreen, the National Bowel Screening Programme in Ireland.

Methods

A retrospective cohort study was conducted. False-positivity was defined as a positive faecal immunochemical test with subsequent colonoscopy showing no evidence of malignancy or surveillance requirement. In those with a false-positive faecal immunochemical test, logistic regression was used to predict repeat participation in the second round.

Results

Of 196,149 individuals who attended the first screening round, 108,075 were eligible and re-invited in the second round, and 93,971 accepted the invitation (86.9%). Second round uptake was higher in faecal immunochemical test-negative individuals compared with those having false-positive results (87.5% vs. 73.1%; p < 0.001). Older age (odds ratio (OR) 0.75; 95% confidence interval (CI) 0.60–0.94), computed tomography colonography (unsuitability/failed colonoscopy) (OR 0.40; 95% CI 0.21–0.73), and longer duration from screening invitation to faecal immunochemical test result (OR 0.991; 95% CI 0.9872–0.995) were predictors of non-re-attendance in the next screening round.

Conclusion

There is a significant reduction in re-attendance rates for individuals with false-positive faecal immunochemical test results. The letter sent following a negative colonoscopy is being reviewed to ensure that it provides adequate encouragement to re-attend. There are roles for screening promotion and for Gastroenterologists and Advanced Nurse Practitioners to emphasize the importance of regular faecal immunochemical tests after a negative colonoscopy.

Screening individuals' experiences of colonoscopy and colon capsule endoscopy; a mixed methods study

BACKGROUND

The standard investigation in colorectal cancer screening (optical colonoscopy [OC]) has a less invasive alternative with the colon capsule endoscopy (CCE). The experiences of screening individuals are needed to support a decision aid (DA) and to provide a patient view in future health technology assessments (HTA). We aimed to explore the experiences of CCE at home and OC in an outpatient clinic by screening participants who experienced both investigations on the same bowel preparation.

METHODS

In a mixed methods study, Danish screening individuals with a positive immunological fecal occult blood test (FIT) were consecutively included and underwent both CCE and OC in the same bowel preparation. They answered questionnaires about discomfort during CCE, delivered at home, and during a following OC in the outpatient clinic. Data were calculated in percentages and Wilcoxon signed rank test was used for comparisons. Among the 253 included patients, 10 participants were selected for a semi-structured interview about their experiences of the two examinations. The analysis and interpretation of the transcribed data were inspired by Ricoeur.

RESULTS

Questionnaire data were received from 239 participants and revealed significant less discomfort during the CCE than the OC. Interview data included explained discomfort elements in two categories: 'The examination' and 'The setting'. Compared to OC, the CCE was experienced with less pain, embarrassment and invasiveness, but presented challenges and disadvantages as well, i.e., a large camera capsule to swallow, a longer waiting time for test results after CCE and an additional OC, if pathologies were found. The home setting for CCE delivery made the participants feel less like they were ill or patients less restricted and that they received more personal care, but could induce technical challenges.

CONCLUSION

In screening individuals, CCE at home was associated with significantly less discomfort compared to OC at a hospital, and multiple reasons for this was identified.

Eliciting vulnerable patients' preferences regarding colorectal cancer screening: a systematic review

BACKGROUND

Patient preferences are important to consider in the decision-making process for colorectal cancer (CRC) screening. Vulnerable populations, such as racial/ethnic minorities and low-income, veteran, and rural populations, exhibit lower screening uptake. This systematic review summarizes the existing literature on vulnerable patient populations' preferences regarding CRC screening.

METHODS

We searched the CINAHL, PsycINFO, PubMed, Scopus, and Web of Science databases for articles published between January 1, 1996 and December 31, 2017. We screened studies for eligibility and systematically abstracted and compared study designs and outcomes.

RESULTS

A total of 43 articles met the inclusion criteria, out of 2,106 articles found in our search. These 43 articles were organized by the primary sub-population(s) whose preferences were reported: 27 report on preferences among racial/ethnic minorities, eight among low-income groups, six among veterans, and two among rural populations. The majority of studies (n=34) focused on preferences related to test modality. No single test modality was overwhelmingly supported by all sub-populations, although veterans seemed to prefer colonoscopy. Test attributes such as accuracy, sensitivity, cost, and convenience were also noted as important features. Furthermore, a preference for shared decision-making between vulnerable patients and providers was found.

CONCLUSION

The heterogeneity in study design, populations, and outcomes of the selected studies revealed a wide spectrum of CRC screening preferences within vulnerable populations. More decision aids and discrete choice experiments that focus on vulnerable populations are needed to gain a more nuanced understanding of how vulnerable populations weigh particular features of screening methods. Improved CRC screening rates may be achieved through the alignment of vulnerable populations' preferences with screening program design and provider practices. Collaborative decision-making between providers and vulnerable patients in preventive care decisions may also be important.

Modeling Individual Patient Preferences for Colorectal Cancer Screening Based on Their Tolerance for Complications Risk

INTRODUCTION

Recommendations for colorectal cancer screening encourage patients to choose among various screening methods based on individual preferences for benefits, risks, screening frequency, and discomfort. We devised a model to illustrate how individuals with varying tolerance for screening complications risk might decide on their preferred screening strategy.

METHODS

We developed a discrete-time Markov mathematical model that allowed hypothetical individuals to maximize expected lifetime utility by selecting screening method, start age, stop age, and frequency. Individuals could choose from stool-based testing every 1 to 3 years, flexible sigmoidoscopy every 1 to 20 years with annual stool-based testing, colonoscopy every 1 to 20 years, or no screening. We compared the life expectancy gained from the chosen strategy with the life expectancy available from a benchmark strategy of decennial colonoscopy.

RESULTS

For an individual at average risk of colorectal cancer who was risk neutral with respect to screening complications (and therefore was willing to undergo screening if it would actuarially increase life expectancy), the model predicted that he or she would choose colonoscopy every 10 years, from age 53 to 73 years, consistent with national guidelines. For a similar individual who was moderately averse to screening complications risk (and therefore required a greater increase in life expectancy to accept potential risks of colonoscopy), the model predicted that he or she would prefer flexible sigmoidoscopy every 12 years with annual stool-based testing, with 93% of the life expectancy benefit of decennial colonoscopy. For an individual with higher risk aversion, the model predicted that he or she would prefer 2 lifetime flexible sigmoidoscopies, 20 years apart, with 70% of the life expectancy benefit of decennial colonoscopy.

CONCLUSION

Mathematical models may formalize how individuals with different risk attitudes choose between various guideline-recommended colorectal cancer screening strategies.

Effect of listening to music and essential oil inhalation on patients undergoing screening CT colonography: a randomized controlled trial

OBJECTIVE

To prospectively evaluate the effect of listening to music and inhaling aroma oil on patients undergoing screening computed tomography colonography.

MATERIALS AND METHODS

Two hundred and twenty four participants were randomly allocated to one of the four groups including: (1) combined music and aroma, (2) music alone, (3) aroma alone, and (4)control. The visual analog scale for pain and a questionnaire were used for subjective outcomes. We also used a pre-test–post-test design to compare the differences in blood pressure and heart rate as objective outcomes.

RESULTS

There were no statistical differences between the control group and other groups in the visual analog scale or changes in heart rate. Changes in blood pressure were similar. Participants reported good overall experiences. There were no differences in terms of overall satisfaction, pain rating, willingness to repeat the computed tomography colonography procedure in the future, or preference between colonoscopy and computed tomography colonography. More participants using music and/or aroma requested music and/or aroma during the next computed tomography colonography (P < 0.0001).

CONCLUSION

Although audio and olfactory intervention had little effect on perceived pain or discomfort and vital signs, participants who listened to music and inhaled aroma during the computed tomography colonography preferred music and aroma during the next computed tomography colonography.

A multi-centre randomised double-blind placebo-controlled trial to evaluate the value of a single bolus intravenous alfentanil in CT colonography

Background

Pain is common during colonic insufflation required for CT colonography. We therefore evaluate whether a single intravenous alfentanil bolus has a clinically relevant analgesic effect compared with placebo in patients undergoing CT colonography.

Methods

A prospective multi-centre randomised double-blind placebo-controlled trial was performed in patients scheduled for elective CT colonography. Patients were randomised to receive either a bolus of 7.5 μg/kg alfentanil (n = 45) or placebo (n = 45). The primary outcome was the difference in maximum pain during colonic insufflation on an 11-point numeric rating scale. We defined a clinically relevant effect as a maximum pain reduction of at least 1.3 points. Secondary outcomes included total pain and burden of CT colonography (5-point scale), the most burdensome aspect and side effects. Our primary outcome was tested using a one-sided independent samples t-test.

Results

Maximum pain scores during insufflation were lower with alfentanil as compared with placebo, 5.3 versus 3.0 (P < 0.001). Total CT colonography pain and burden were also lower with alfentanil (2.0 vs. 1.6; P = 0.014 and 2.1 vs. 1.7; P = 0.007, respectively). With alfentanil fewer patients rated the insufflation as most burdensome aspect (56.1% vs. 18.6%; P = 0.001). Episodes with desaturations < 90% SpO2 were more common with alfentanil (8.1% vs. 44.4%; P < 0.001, but no clinically relevant desaturations occurred.

Conclusions

A low-dose intravenous alfentanil bolus provides a clinically relevant reduction of maximum pain during CT colonography and may improve the CT colonography acceptance, especially for patients with a low pain threshold.

Trial registration

Dutch Trial Register: NTR2902

WHAT ARE THE MOST IMPORTANT FACTORS REGARDING ACCEPTANCE TO THE COLONOSCOPY?

ContextColonoscopy plays an indubitable role in the setting of clinical practice, however, it is an invasive exam; complex, lengthy, embarrassing, not devoid of risks and discomfort that yields fear and anxiety in the majority of patients. In a new era of rising competition between health institutions, where the quality of health care and client satisfaction are praised, studies regarding tolerance-related colonoscopy issues yield great potential to be explored. In the present study, tolerance is defined as willingness to repeat the exam.ObjectivesEvaluate information associated to bowel preparation, the exam itself and post-examination period that might interfere with the tolerance to the colonoscopy.MethodsAnalysis of the tolerance to the colonoscopy at three stages (pre, post, and during) through a checklist: patient's questionnaire and a medical assessment form were used.ResultsIn this present study, 91.2% of 373 patients exhibited positive tolerance to the colonoscopy. Aspects related to a negative level of tolerance were patient gender (12.9% of women versus 3.2% of men would not repeat the exam), age extremes (less than 20 years and greater than 80 years of age), and abdominal pain, both during the bowel preparation and after the procedure.ConclusionsGender, age, patient cooperation and abdominal pain were the decisive components regarding tolerance to the colonoscopy. Notably, in two phases of the exam, the abdominal pain was the most important feature associated to a lessened tolerance.

Preference for colonoscopy versus computerized tomographic colonography: a systematic review and meta-analysis of observational studies

In recent years, colorectal cancer (CRC) screening using computerized tomographic colonography (CTC) has attracted considerable attention. In order to better understand patient preferences for CTC versus colonoscopy, we performed a systematic review and meta-analysis of the available literature. Data sources included published studies, abstracts and book chapters, in any language, with publication dates from 1995 through February 2012, and with prospective or retrospective enrollment of diagnostic or screening patients who had undergone both procedures and explicit assessment of their preference for colonoscopy versus CTC. A predefined algorithm identified eligible studies using computer and hand searches performed by two independent investigators. We used a mixed effects model to pool preference differences (defined as the proportion of subjects who preferred CTC minus the proportion who preferred colonoscopy for each study). Twenty-three studies met inclusion criteria, totaling 5616 subjects. In 16 of these studies, patients preferred CTC over colonoscopy, while colonoscopy was preferred in three studies. Due to the high degree of heterogeneity, an overall pooled preference difference was not calculated. Stratified analysis revealed that studies published in radiology journals (preference difference 0.590 [95 % CI 0.485, 0.694]) seemed more likely than studies in gastroenterology (0.218 [-0.015-0.451]) or general medicine journals (-0.158 [-0.389-0.072]) to report preference for CTC (p<0.001). Studies by radiology authors showed a trend towards stronger preference for CTC compared with studies by gastroenterology authors. Symptomatic patients expressed no preference, but screening patients preferred CTC. There was no difference in preferences between studies using "masked" and "unmasked" preference ascertainment methods. Three studies featuring limited bowel preparations for CTC reported marked preference for CTC. There was no evidence of publication bias, while cumulative and exclusion analysis did not show any temporal trend or dominant study. Limitations included data heterogeneity and preference ascertainment limitations. In conclusion, most included studies reported preference for CTC. On stratified analysis, screening patients preferred CTC while diagnostic patients showed no preference. Studies published in radiology journals showed significantly stronger preference for CTC compared with studies in gastroenterology or general medicine journals.

Preferência do paciente no rastreamento do câncer colorretal: uma comparação entre colonografia por tomografia computadorizada e colonoscopia

OBJETIVO: Avaliar o grau de aceitação do paciente submetido a colonografia por tomografia computadorizada (CTC) em comparação com a colonoscopia, quando realizadas para rastreamento de doença colorretal. MATERIAIS E MÉTODOS: Cinquenta pacientes com suspeita de doença colorretal foram submetidos a CTC e colonoscopia. Questionários foram aplicados antes e após a realização da CTC e após a colonoscopia. Graduou-se o desconforto esperado e experimentado antes e após a realização da CTC e da colonoscopia, bem como a preferência do paciente por exame. RESULTADOS: Em relação à CTC, antes de iniciar o exame 18% dos pacientes afirmaram esperar pouco desconforto, 78%, desconforto moderado e 4%, muito desconforto. Após a realização do exame, 72% dos pacientes relataram pouco desconforto, 26%, desconforto moderado e apenas um (2%) dos pacientes referiu muito desconforto. Após a realização da colonoscopia, 86% dos pacientes relataram preferência pela CTC. O grau de distensão colônica e a quantidade de fluido residual não influenciaram na preferência dos pacientes. CONCLUSÃO: Os pacientes preferiram a CTC à colonoscopia, não havendo relação estatística com o grau de distensão colônica na CTC e a eficiência do preparo intestinal.

Colon distension and scan protocol for CT-colonography: an overview

This article reviews two important aspects of CT-colonography, namely colonic distension and scan parameters. Adequate distension should be obtained to visualize the complete colonic lumen and optimal scan parameters should be used to prevent unnecessary radiation burden. For optimal distension, automatic carbon dioxide insufflation should be performed, preferably via a thin, flexible catheter. Hyoscine butylbromide is - when available - the preferred spasmolytic agent because of the positive effect on insufflation and pain/burden and its low costs. Scans in two positions are required for adequate distension and high polyp sensitivity and decubitus position may be used as an alternative for patients unable to lie in prone position. The great intrinsic contrast between air or tagging and polyps allows the use of low radiation dose. Low-dose protocol without intravenous contrast should be used when extracolonic findings are deemed unimportant. In patients suspected for colorectal cancer, normal abdominal CT scan protocols and intravenous contrast should be used in supine position for the evaluation of extracolonic findings. Dose reduction can be obtained by lowering the tube current and/or voltage. Tube current modulation reduces the radiation dose (except in obese patients), and should be used when available. Iterative reconstructions is a promising dose reducing tool and dual-energy CT is currently evaluated for its applications in CT-colonography. This review also provides our institution's insufflation procedure and scan parameters.

Preferences for CT colonography and colonoscopy as diagnostic tests for colorectal cancer: a discrete choice experiment

OBJECTIVE

Computed tomography colonography (CTC) is an alternative diagnostic test to colonoscopy for colorectal cancer and polyps. The aim of this study was to determine test characteristics important to patients and to examine trade-offs in attributes that patients are willing to accept in the context of the diagnosis of colorectal cancer.

METHODS

A discrete choice study was used to assess preferences of patients with clinical indications suspicious of colorectal cancer who experienced both CTC and colonoscopy as part of a diagnostic accuracy study in South Australia. Results were analyzed by using a mixed logit model and presented as odds ratios (ORs) for preferring CTC over colonoscopy.

RESULTS

Colonoscopy was preferred over CTC as the need for a second procedure after CTC increased (OR of preferring CTC to colonoscopy = 0.013), as the likelihood of missing cancers or polyps increased (OR of preferring CTC to colonoscopy = 0.62), and as CTC test cost increased (OR of preferring CTC to colonoscopy = 0.65-0.80). CTC would be preferred to colonoscopy if a minimal bowel preparation was available (OR = 1.7). Some patients were prepared to trade off the diagnostic and therapeutic advantage of colonoscopy for a CTC study with a less intensive bowel preparation. Preferences also varied significantly with sociodemographic characteristics.

CONCLUSIONS

Despite CTC's often being perceived as a preferred test, this may not always be the case. Informed decision making for diagnostic tests for colorectal cancer should include discussion of the benefits, downsides, and uncertainties associated with alternative tests, as patients are willing and able to make trade-offs between what they perceive as the advantages and disadvantages of these diagnostic tests.

A randomized double-blind placebo-controlled trial to evaluate the value of a single bolus intravenous alfentanil in CT colonography

BACKGROUND

Although CT colonography is a less invasive alternative for colonoscopy for the detection of colorectal polyps and cancer, procedural pain is common. In several studies, CT colonography pain and burden is higher than in colonoscopy. Apart from discomfort, anxiety and its related stress-induced peri- procedural side effects, this may influence the adherence for CT colonography as a possible screening tool for colorectal cancer. We hypothesize that a single bolus intravenous alfentanil will give a clinically relevant reduction in maximum pain defined as at least 1.3 point reduction on an 11-point numeric rating scale (NRS).

METHODS/DESIGN

A randomized double-blind placebo-controlled trial in which patients scheduled for elective CT colonography in a single tertiary centre are eligible for inclusion. The first 90 consenting patient will be block-randomized to either the alfentanil group or the placebo group. Before bowel insufflation, the alfentanil group receives a single bolus intravenous alfentanil 7.5 μg/kg dissolved in 0.9% NaCl, while the placebo group receives an intravenous bolus injection of pure 0.9% NaCl. For both groups an equal amount of fluid per kilogram (75 μL/kg) is injected. The primary outcome is the difference in maximum pain on an 11-point NRS. Secondary outcomes include: pain and burden of different CT colonography aspects, side effects, procedural time and recovery time. For the primary outcome an independent samples t-test is performed and a P value<0.05 is considered statistically significant.

DISCUSSION

This study will provide evidence whether a single bolus intravenous alfentanil gives a clinically relevant reduction in maximum pain during CT colonography.

TRIAL REGISTRATION

Netherlands Trial Register (NTR): NTR2902. This trial will be conducted in accordance with the protocol and in compliance with the moral, ethical, and scientific principles governing clinical research as set out in the Declaration of Helsinki (1989) and Good Clinical Practice (GCP). The department of radiology of the Academic Medical Center of Amsterdam is responsible for the design and conduct of the trial.

Comparative economic evaluation of data from the ACRIN National CT Colonography Trial with three cancer intervention and surveillance modeling network microsimulations

PURPOSE

To estimate the cost-effectiveness of computed tomographic (CT) colonography for colorectal cancer (CRC) screening in average-risk asymptomatic subjects in the United States aged 50 years.

MATERIALS AND METHODS

Enrollees in the American College of Radiology Imaging Network National CT Colonography Trial provided informed consent, and approval was obtained from the institutional review board at each site. CT colonography performance estimates from the trial were incorporated into three Cancer Intervention and Surveillance Modeling Network CRC microsimulations. Simulated survival and lifetime costs for screening 50-year-old subjects in the United States with CT colonography every 5 or 10 years were compared with those for guideline-concordant screening with colonoscopy, flexible sigmoidoscopy plus either sensitive unrehydrated fecal occult blood testing (FOBT) or fecal immunochemical testing (FIT), and no screening. Perfect and reduced screening adherence scenarios were considered. Incremental cost-effectiveness and net health benefits were estimated from the U.S. health care sector perspective, assuming a 3% discount rate.

RESULTS

CT colonography at 5- and 10-year screening intervals was more costly and less effective than FOBT plus flexible sigmoidoscopy in all three models in both 100% and 50% adherence scenarios. Colonoscopy also was more costly and less effective than FOBT plus flexible sigmoidoscopy, except in the CRC-SPIN model assuming 100% adherence (incremental cost-effectiveness ratio: $26,300 per life-year gained). CT colonography at 5- and 10-year screening intervals and colonoscopy were net beneficial compared with no screening in all model scenarios. The 5-year screening interval was net beneficial over the 10-year interval except in the MISCAN model when assuming 100% adherence and willingness to pay $50,000 per life-year gained.

CONCLUSION

All three models predict CT colonography to be more costly and less effective than non-CT colonographic screening but net beneficial compared with no screening given model assumptions.

Analysis of barriers to and patients' preferences for CT colonography for colorectal cancer screening in a nonadherent urban population

OBJECTIVE

The aim of this study was to evaluate patients' barriers against colorectal cancer screening tests and to assess patients' preferences and cost influences for CT colonography (CTC) in a nonadherent urban subpopulation.

SUBJECTS AND METHODS

Patients who had been offered colorectal cancer screening but were nonadherent were asked to participate in this questionnaire study. Patients' demographic information was obtained, and patients' reasons for not being screened were explored. Subjects were given an information sheet that described a CTC procedure and then were asked about their willingness to undergo CTC and about other relevant factors, such as fees.

RESULTS

One hundred seventy-five patients were invited to participate; 53 declined and 54 did not respond, which left 68 subjects to be included in the analysis. After being informed about CTC screening, most (83%) subjects stated that they would be willing to undergo a CTC study. However, 70% stated that they would not be willing to pay out-of-pocket fees if insurance did not cover the study, and even among the 30% who were willing to pay the fees, the average amount they were willing to pay (mean, $244; median, $150) was well below currently charged rates.

CONCLUSION

Our study suggests that most nonadherent patients would be willing to undergo CTC as long as out-of-pocket fees are reasonable.

CT colonography with decreased purgation: balancing preparation, performance, and patient acceptance

OBJECTIVE

Reduction or elimination of catharsis with fecal tagging enhances the tolerability of CT colonography (CTC) and may increase compliance with colorectal cancer (CRC) screening recommendations. We systematically reviewed studies that prospectively evaluated performance and patient satisfaction with decreased-purgation CTC and with optical colonoscopy.

CONCLUSION

The nine studies reviewed showed moderate-to-good performance for decreased-purgation CTC; however, data are limited, and study design and data presentation are inconsistent. Further study of decreased-purgation CTC and standardization of terminology are needed.

Virtual endoscopy using CT scan

The term virtual endoscopy refers to using either spiral computed tomography (CT colonography) or magnetic resonance scanning (MR colonography) combined with computer technology to produce high-resolution two- and three-dimensional imaging of the large bowel. Current CT techniques require meticulous bowel preparation and gas insufflation prior to the examination. The advantages of CT colonography over conventional colonography include safety, its ability to demonstrate the entire large bowel in almost all patients, even following incomplete endoscopy, to accurately localize lesions, and to examine the entire colon in patients with obstructing tumors. Additionally, CT colonography allows simultaneous preoperative tumor staging. Screening for colorectal polyps is a controversially discussed indication for CT colonography. Sensitivity and specificity range widely and decrease with decreasing polyp size. However, better results can be achieved using multidetector technology. Most frequently, the examination is well tolerated and assessed by patients to be more acceptable than conventional colonoscopy. There are no reported complications from CT colonography. The procedure requires a scan time of about 25 to 30 seconds with new multidetector CT scanners, and sedation is not used. Currently, CT colonography is less cost-effective than conventional endoscopy. Another disadvantage is the relatively high irradiation exposure associated with CT colonography. Therefore, at the moment, this technique does not appear ready to be included in general screening strategies. However, ongoing and future improvements may prove its value in colorectal examination strategies.

Computed tomographic colonography: current perspectives and future directions

Computed tomographic (CT) colonography, also known as virtual colonoscopy or CT colography, is capable of detecting colon polyps and cancers. It is emerging rapidly and has gained great momentum over the past several years, to the point where it has been proposed to be a viable primary colon cancer screening option. Despite the current publicity, many issues concerning CT colonography remain. As of 2009, the following topics are of paramount importance: (1) accuracy, including both sensitivity and specificity, (2) bowel preparation, (3) safety, (4) extracolonic findings, (5) patient acceptability, (6) training and standardization, and (7) implementation of CT colonography. Although much about CT colonography has already been learned, more remains to be learned in the future.

[Indications for and results of CT colonography: from screening to the symptomatic patient]

CT colonography (CTC) is also referred to as virtual colonoscopy and is being used with increasing frequency in radiological practice. While there are still no generally accepted, clear-cut indications for its use in mass colorectal cancer screening, there is evidence that this investigation is useful in patients in whom colonoscopy has not been successful or who have known stenotic lesions in the colon. Recent results of significant comparative studies of CTC and conventional colonoscopy will have some influence on the future place of CTC in screening for cancer of the bowel; they show the great potential of CT-aided bowel examination.

Patient satisfaction with colonoscopy: a literature review and pilot study

BACKGROUND

Current guidelines recommend that colonoscopic colorectal cancer screening be undertaken every 10 years after the age of 50 years. However, because the procedure does not meet criteria that promote screening uptake, patient satisfaction with colonoscopy may encourage repeat screening.

OBJECTIVE

To systematically review the literature and conduct a pilot study of patient satisfaction with the colonoscopy experience.

METHODS

All cohort studies from January 1997 to August 2008 in the MEDLINE database that measured either patient satisfaction with colonoscopy, patient willingness to return for colonoscopy under the same conditions or patient preference for colonoscopy compared with other large bowel procedures were identified. The search was supplemented by journal citation lists in the retrieved articles.

RESULTS

Of the 29 studies identified, 15 met the inclusion criteria. Consistently, the vast majority of patients (approximately 95%) were very satisfied with their colonoscopy experience. Patient satisfaction was similar for screening and nonscreening colonoscopy. Patient willingness to return for the procedure ranged from 73% to 100%. Of the five studies that examined modality preference, three studies reported the majority of patients preferred colonography to colonoscopy and two studies reported the reverse. Our pilot study findings mirrored those of other studies that were conducted in the United States. The major limitation of the included studies was that patients who were most dissatisfied may have gone elsewhere to have their colonoscopy.

CONCLUSIONS

Patients were very satisfied with colonoscopy. The majority were willing to return for repeat testing under the same conditions, and colonoscopy was not preferred over other modalities. However, studies were limited by methodological shortcomings.

A comparison of patient acceptance and preferences between CT colonography and conventional colonoscopy in colorectal cancer screening

BACKGROUND/AIMS

Colorectal cancer, one of the most common cancers in developed countries, is curable when diagnosed at an early stage. However, for better screening, both a test that patients will tolerate and diagnostic accuracy are required. We compared patient experiences and preferences between computed tomographic (CT) colonography and conventional colonoscopy (CC) under conscious sedation.

METHODS

Patients referred to the gastrointestinal clinic for CC were enrolled to also undergo CT colonography prior to CC. After each procedure, patients completed a questionnaire in which variables, such as abdominal pain, abdominal discomfort, and loss of dignity, were assessed using a 7-point Likert scale, with the highest score representing the worst experience. To verify response stability, a telephone questionnaire followed within 24 h after each procedure. Patients were then asked about their preference for CT colonography or CC.

RESULTS

Data were collected from 51 patients who fulfilled all requirements, including CT colonography, CC, the two questionnaires after each procedure, and a follow-up questionnaire. Severity of abdominal pain, abdominal discomfort, and a loss of dignity were reported to be higher in CT colonography than in CC (p<0.01). In addition, the preference for CC was significantly higher than that for CT colonography (p<0.01).

CONCLUSIONS

Although CT colonography is a safe and noninvasive screening test for colorectal cancer, further study is required to increase patient acceptance.

Patient experiences of colonoscopy, barium enema and CT colonography: a qualitative study

Previous studies of patient experience with bowel screening tests, in particular CT colonography (CTC), have superimposed global rating scales and not explored individual experience in detail. To redress this, we performed qualitative interviews in order to characterize patient expectations and experiences in depth. Following ethical permission, 16 patients undergoing CTC, 18 undergoing colonoscopy and 15 undergoing barium enema agreed to a semi-structured interview by a health psychologist. Interviews were recorded, responses transcribed and themes extracted with the aim of assimilating individual experiences to facilitate subsequent development and interpretation of quantitative surveys of overall satisfaction with each diagnostic test. Transcript analysis identified three principal themes: physical sensations, social interactions and information provision. Physical sensations differed for each test but were surprisingly well tolerated overall. Social interactions with staff were perceived as very important in colouring the whole experience, particularly in controlling the feelings of embarrassment, which was critical for all procedures. Information provision was also an important determinant of experience. Verbal feedback was most common during colonoscopy and invariably reassuring. However, patients undergoing CTC received little visual or verbal feedback and were often confused regarding the test outcome. Barium enema had no specific advantage over other tests. Qualitative interviews provided important perspectives on patient experience. Our data demonstrated that models describing the quality of medical encounters are applicable to single diagnostic episodes. Staff interactions and information provision were particularly important. We found advantages specific to both CTC and colonoscopy but none for barium enema. CTC could benefit greatly from improved information provision following examination.

Computed tomography colonography (virtual colonoscopy): climax of a new era of validation and transition into community practice

Colorectal cancer, which kills more than 50,000 patients every year in the United States and costs more than $6 billion in direct health costs, is a prime target for cancer prevention. Computed tomography colonography (CTC) has emerged as a minimally invasive, structural examination of the entire colon that can complement the current tools of cancer prevention and may improve patient compliance. Large trials have suggested a sensitivity of roughly 90% and specificity greater than 97% for CTC for patients with polyps >or= 10 mm. Bowel preparation by diet restriction, catharsis, and stool and fluid tagging are typically used. A prepless CTC protocol is an active area of research with a focus on improving patient compliance. Insurance coverage of CTC is a key factor affecting current dissemination and local and national coverage decisions are ongoing. CT examination of the abdomen allows visualization of extracolonic organs, where detection of additional disease must balance any unnecessary anxiety and testing. Estimates of CTC cost-effectiveness are generally favorable, but vary due to the high sensitivity of these models to costs, polyp sensitivity, compliance rates, and other parameters, which are difficult to accurately assess. Quality initiatives are being developed that will be key for implementation into community practice.

Racial/ethnic differences in patient experiences with and preferences for computed tomography colonography and optical colonoscopy

BACKGROUND & AIMS

Racial/ethnic minorities are less likely than whites to undergo colorectal cancer (CRC) screening. Although computed tomography colonography (CTC) is a less invasive alternative to optical colonoscopy (OC), it is not known whether CTC will increase acceptance of CRC screening in minorities.

METHODS

Patients undergoing OC for clinically indicated reasons had CTC followed by same-day OC. After the sedation from the OC had worn off, a questionnaire was administered to assess pain, discomfort, bloating, embarrassment, anxiety, and patient satisfaction using a 10-point scale (1 = least, 10 = greatest).

RESULTS

Of the 272 patients enrolled, there were 134 whites, 71 blacks, 53 Hispanics, and 14 who self-identified their race/ethnicity as other. Although the proportion of subjects who preferred CTC over OC was not significantly different (52.9% vs 47.1%, P = .36), racial/ethnic minorities were significantly less likely than whites to prefer CTC over OC (whites, 65.7%; blacks, 45.1%; Hispanics, 35.8%; and other, 35.7%; P < .001). Racial/ethnic minorities were less satisfied with CTC (whites, 8.4 +/- 1.7; blacks, 7.8 +/- 1.7; Hispanics, 7.4 +/- 1.8; and other, 7.5 +/- 2.1; P = .001) and were significantly less willing to undergo CTC again in the future (whites, 95.5%; blacks, 80.3%; Hispanics, 84.9%; and other, 85.7%; P = .006).

CONCLUSIONS

Compared with white patients, OC is better tolerated and is preferred over CTC for evaluation of the colon among racial/ethnic minorities. Although CTC is less invasive than OC, our findings suggest that CTC is unlikely to overcome racial/ethnic disparities in CRC screening.

MR Colonography with Limited Bowel Preparation: Patient Acceptance Compared with That of Full-Preparation Colonoscopy

PURPOSE

To prospectively evaluate participants' experience and preference of magnetic resonance (MR) colonography with limited bowel preparation compared with full-preparation colonoscopy in participants at increased risk for colorectal cancer.

MATERIALS AND METHODS

This study had institutional review board approval; all participants gave written informed consent. In this multicenter study, consecutive participants undergoing conventional colonoscopy because of a personal or family history of colorectal cancer or adenomatous polyps underwent MR colonography 2 weeks prior to colonoscopy. They all followed a low-fiber diet and were given lactulose and an oral contrast agent (fecal tagging with gadolinium) 2 days before colonography. Before imaging, spasmolytics were administered intravenously, and a water-gadolinium chelate mixture was administered rectally for distention of the colon. Breath-hold T1- and T2-weighted sequences were performed in the prone and supine positions. Participant experience in terms of, for example, pain and burden was determined by using a five-point scale and was evaluated with a Wilcoxon signed rank test; participant preference was determined by using a seven-point scale and was evaluated with the chi2 statistic after dichotomizing.

RESULTS

Two hundred nine participants (77 women, 132 men; mean age, 58 years; range, 23-84 years) were included. One hundred forty-eight participants received sedatives (midazolam) and/or analgesics (fentanyl) during colonoscopy. Participants rated the MR colonography bowel preparation as less burdensome (P<.001) compared with the colonoscopy bowel preparation (10% and 71% of participants rated the respective examinations moderately to extremely burdensome). Participants also experienced less pain at MR colonography (P<.001) and found MR colonography less burdensome (P<.001). Immediately after both examinations, 69% of participants preferred MR colonography, 22% preferred colonoscopy, and 9% were indifferent (P<.001, 69% vs 22%). After 5 weeks, 65% preferred MR colonography and 26% preferred colonoscopy (P<.001).

CONCLUSION

Participants preferred MR colonography without extensive cleansing to colonoscopy immediately after both examinations and 5 weeks later. Experience of the bowel preparation and of the procedure was rated better.

CT colonography: an update

Computed tomographic (CT) colonography (CTC)--also known as "virtual colonoscopy"--was first described more than a decade ago. As advancements in scanner technology and three-dimensional (3D) postprocessing helped develop this method to mature into a potential option in screening for colorectal cancer, the fundamentals of the examination remained the same. It is a minimally invasive, CT-based procedure that simulates conventional colonoscopy using 2D and 3D computerized reconstructions. The primary aim of CTC is the detection of colorectal polyps and carcinomas. However, studies reveal a wide performance variety in regard to polyp detection, especially for smaller polyps. This article reviews the available literature, discusses established indications as well as open issues and highlights potential future developments of CTC.

Utility of computed tomographic colonography in surveillance for hereditary nonpolyposis colorectal cancer syndrome

Computed tomographic colonography (CTC) is suggested to be an alternative to colonoscopy as a surveillance tool in subjects with a high risk for colorectal cancer (CRC). To evaluate the utility of CTC we successively examined 78 subjects, all with a DNA mismatch repair gene mutation, by CTC and colonoscopy. We detected altogether 37 polyps or tumors in 28 subjects (prevalence 35.9%), adenomas in 13 subjects (16.7%), CRC in two (2.6%), and hyperplastic polyps in 13 (16.7%). A great majority of the polyps were diminutive. The per-patient sensitivity for detecting all lesions with CTC was 0.25 and 0.29 by two radiologists and the specificities 0.82 and 0.76. For lesions of 10 mm or larger the sensitivities were 0.6 and 1.0 and the specificities 0.96 by each examiner. Each diagnosed the two cancers correctly. We concluded that CTC has an acceptable accuracy for large lesions in the colon but the detection rate for small polyps is not comparable to that in colonoscopy. Therefore CTC remains a second choice in surveillance for use when colonoscopy for some reason is incomplete or unsuitable.

MR colonography without bowel purgation for the assessment of inflammatory bowel diseases: diagnostic accuracy and patient acceptance

BACKGROUND

The purpose of this pilot study was to assess the diagnostic accuracy of MR colonography (MRC) without bowel cleansing regarding its ability to quantify inflammatory bowel disease (IBD). In addition, patient acceptance was compared with conventional colonoscopy (CC).

METHODS

In all, 29 patients with IBD (17 ulcerative colitis; 12 Crohn's disease) were included. While CC was performed after bowel cleansing as the gold standard, MRC was based on a fecal tagging technique and performed 48-72 hours prior to CC. The presence of inflammation in each of 7 ileocolonic segments was rated for every procedure. Patients evaluated both modalities and dedicated aspects of the examination according to a 10-point-scale (1 = good, 10 = poor acceptance). Furthermore, preferences for future examinations were investigated.

RESULTS

Inflammatory segments were found by means of CC in 23 and by MRC in 14 patients. Overall sensitivity and specificity of MRC in a segment-based detection were 32% and 88%, respectively. Concerning severely inflamed segments, sensitivity increased to 53% for MRC. Overall acceptance of CC was significantly higher compared to MRC (mean value (mv) for MRT = 6.0; CC = 4.1; P = 0.003). For MRC, the placement of the rectal tube (mv = 7.3), and for CC bowel purgation (mv = 6.5), were rated as the most unpleasant. A total of 67% of patients voted for CC as the favorable tool for future examinations.

CONCLUSIONS

The presented data indicate that 'fecal tagging MRC' is not suitable for an adequate quantification of inflammatory diseases of the large bowel. Furthermore, overall acceptance of endoscopic colonoscopy was superior to MRC.

MR colonography

Combining the advantages of unsurpassed soft tissue contrast and lack of ionizing radiation, MR imaging of the gastrointestinal tract has become increasingly used clinically. Both bowel inflammation and tumor disease of the large bowel can be well visualized by means of MR colonography (MRC). This article describes current techniques of MRC and gives an overview of its clinical outcome. Special focus is directed toward the evaluation of patients' acceptance of MRC.

The evolving role of CT colonography

Colorectal cancer (CRC) screening is widely recommended as part of standard preventive care. All average risk persons over the age of 50 y are eligible. Various authorities have advocated fecal occult blood testing, flexible sigmoidoscopy, barium enema and colonoscopy at varying intervals as acceptable screening options. Despite the array of choices, CRC screening lags in frequency behind other cancer screening maneuvers like mammography or Pap smear. Of late, there is growing interest in CT colonography (CTC) as another screening option. CTC, or virtual colonoscopy, may represent an attractive, non-invasive method of CRC screening that provides images akin to traditional colonoscopy. Improvements in CTC performance, especially when coupled with declining costs, suggest that CTC's role in average risk screening will increase in the future. This review summarizes available data about the efficacy of CTC in average and high risk screening populations. Current indications as well as limitations to this technology are discussed, as are practical issues like the cost-effectiveness of CTC for widespread use.

Feasibility study of computed tomography colonography using limited bowel preparation at normal and low-dose levels study

The purpose was to evaluate low-dose CT colonography without cathartic cleansing in terms of image quality, polyp visualization and patient acceptance. Sixty-one patients scheduled for colonoscopy started a low-fiber diet, lactulose and amidotrizoic-acid for fecal tagging 2 days prior to the CT scan (standard dose, 5.8–8.2 mSv). The original raw data of 51 patients were modified and reconstructed at simulated 2.3 and 0.7 mSv levels. Two observers evaluated the standard dose scan regarding image quality and polyps. A third evaluated the presence of polyps at all three mSv levels in a blinded prospective way. All observers were blinded to the reference standard: colonoscopy. At three times patients were given questionnaires relating to their experiences and preference. Image quality was sufficient in all patients, but significantly lower in the cecum, sigmoid and rectum. The two observers correctly identified respectively 10/15 (67%) and 9/15 (60%) polyps ≥10 mm, with 5 and 8 false-positive lesions (standard dose scan). Dose reduction down to 0.7 mSv was not associated with significant changes in diagnostic value (polyps ≥10 mm). Eighty percent of patients preferred CT colonography and 13% preferred colonoscopy (P<0.001). CT colonography without cleansing is preferred to colonoscopy and shows sufficient image quality and moderate sensitivity, without impaired diagnostic value at dose-levels as low as 0.7 mSv.

MR colonography vs. optical colonoscopy: comparison of patients’ acceptance in a screening population

The aim of this study was to compare optical colonoscopy to fecal-tagging-based MR colonography in a screening population in terms of comfort and acceptance ratings as well as for future preferences as colorectal cancer screening examinations. Two hundred eighty-four asymptomatic patients (mean age 59 years) underwent MRC and OC within 4 weeks. While MRC was based on a fecal tagging technique, OC was performed after bowel cleansing. For OC, sedatives and analgesics were used. Patients evaluated both modalities and certain aspects of the examination according to a 10-point-scale with higher scores denoting a worse experience. Furthermore, preferences for future examinations were evaluated. No significant difference was noted for the overall acceptance of OC (mean value 3.0) and MRC (mean value 3.4). For MRC, the placement of the rectal tube was rated as the most unpleasant part, whereas bowel purgation was regarded most inconvenient for OC. Patients aged 55 years and older perceived most aspects less unpleasant than younger patients. Of the patients, 46% preferred MRC for future screening examinations (OC: 44%). OC and MRC have comparable general acceptance levels in a screening population. Especially for patients declining endoscopy as a screening method MRC may evolve as an attractive alternative.

Prospective comparison of patient experience with colon imaging tests

PURPOSE

Patient experience varies with the currently available colon imaging tests, including air contrast barium enema, computed tomographic colonography, and colonoscopy. We examined differences in patient experience with colon imaging tests and whether they varied with gender, age, and race.

SUBJECTS AND METHODS

Patients with fecal occult blood, hematochezia, iron-deficiency anemia, or a family history of colon cancer underwent air contrast barium enema followed 7 to 14 days later by computed tomographic colonography and colonoscopy. Validated patient experience questionnaires that measured the experience for each test and a separate questionnaire that obtained an overall summary measure were administered after testing. Eleven patient experiences including pain, embarrassment, difficulty with bowel preparation, and satisfaction with tests were examined.

RESULTS

A total of 614 subjects completed all 3 imaging tests. The test most patients were willing to repeat was colonoscopy; it also was reported to be the least painful procedure. Patients were least satisfied with air contrast barium enema, and fewer would undergo air contrast barium enema compared with computed tomographic colonography or colonoscopy. There were limited racial and gender differences in perceptions of the tests. Younger adults perceived air contrast barium enema to be more painful than older adults.

CONCLUSION

Taking into account a wide variety of patient experience measures, patients preferred colonoscopy to air contrast barium enema and computed tomographic colonography. This finding has important implications for physicians considering different colon imaging tests.

MR colonography: current status

Magnetic resonance colonography (MRC) has gained access into clinical routine as a means for the assessment of the large bowel. There are widely accepted indications for MRC, especially in patients with incomplete conventional colonoscopy. Furthermore, virtual MRC is more and more propagated as a screening tool, with advantages especially inherent to the non-invasive character of this procedure and the lack of ionizing radiation exposition. Beyond a sufficiently high diagnostic accuracy, outstanding patient acceptance is a major advantage of MRC as a diagnostic modality. This review article describes indications, techniques and clinical outcome of current MRC approaches. Furthermore, the impact of fecal tagging concepts is discussed.

Advanced imaging and technology in gastrointestinal neoplasia: summary of the AGA-NCI Symposium October 4-5, 2004

Imaging and other advanced technologies for detection of gastrointestinal cancers are undergoing a major revolution on several fronts. This is facilitated by convergence of key technologies including advanced endoscopic-detection systems, more specific contrast agents, rapid and high-resolution cross-sectional imaging, and miniaturization of construction systems for making all imaging equipment smaller and less invasive. This convergence is occurring along traditional translational research pathways (clinical medicine-molecular biology) as well as nontraditional lines (clinical medicine-optical physics/engineering and molecular biology-optical physics/engineering). These new efforts are producing a wide array of technologies aimed at improving detection, classification, and monitoring of gastrointestinal neoplasia, especially for colorectal and esophageal cancer because of easier accessibility. A critical goal is to detect lesions at their premalignant stages, thereby permitting meaningful intervention. Inspired by these advances, the American Gastroenterological Association and the National Cancer Institute sponsored a symposium held in Bethesda, MD, from October 4-5, 2004, bringing together leading investigators with diverse backgrounds in imaging technology. The aims of this symposium were to summarize the state of the art and priorities for research in the coming decade in the field of imaging and advanced technology for gastrointestinal neoplasia. In this overview, we summarize the salient results of that symposium. The initial sections discuss the major technologies in each area of endoluminal imaging and molecular imaging followed by applications to specific diseases such as Barrett's esophagus and colon neoplasia. Each section focuses on the current state of the art then lists major priorities for research in the field.

Computed tomography colonography: current issues

OBJECTIVE

Direct and indirect evidence supports the concept of screening for adenomas and early stage colorectal cancer in reducing the incidence and disease-specific mortality. Controversy remains as to the appropriateness of and preferred methods for screening an asymptomatic population.

METHODS

Review of computed tomography (CT) colonography based on the literature and personal experience.

RESULTS AND CONCLUSIONS

Current discrepancies in the data on accuracy and patient acceptance of CT colonography reflect differences in the performance and evaluation of this examination. Before CT colonography can be implemented in colorectal cancer screening, factors that cause this variability must be elucidated. Studies in which high-resolution scanning, three-dimensional review methods and an enhanced colonoscopic reference are used achieve an accuracy that is similar to colonoscopy. At the same time the evidence that ultra-low radiation dose CT colonography is feasible is mounting, a development that dramatically reduces one of the largest obstacles for large-scale application of this technique.

Cost-effectiveness of computerized tomographic colonography versus colonoscopy for colorectal cancer screening

BACKGROUND

Computerized tomographic (CT) colonography is a potential alternative to colonoscopy for colorectal cancer screening. Its main advantage, a better safety profile, may be offset by its limitations: lower sensitivity, need for colonoscopy in cases where results are positive, and expense.

METHODS

We performed an economic evaluation, using decision analysis, to compare CT colonography with colonoscopy for colorectal cancer screening in patients over 50 years of age. Three-year outcomes included number of colonoscopies, perforations and adenomas removed; deaths from perforation and from colorectal cancer from missed adenomas; and direct health care costs. The expected prevalence of adenomas, test performance characteristics of CT colonography and colonoscopy, and probability of colonoscopy complications and cancer from missed adenomas were derived from the literature. Costs were determined in detail locally.

RESULTS

Using the base-case assumptions, a strategy of CT colonography for colorectal cancer screening would cost 2.27 million dollars extra per 100,000 patients screened; 3.78 perforation-related deaths would be avoided, but 4.11 extra deaths would occur from missed adenomas. Because screening with CT colonography would cost more and result in more deaths overall compared with colonoscopy, the latter remained the dominant strategy. Our results were sensitive to CT colonography's test performance characteristics, the malignant risk of missed adenomas, the risk of perforation and related death, the procedural costs and differences in screening adherence.

INTERPRETATION

At present, CT colonography cannot be recommended as a primary means of population-based colorectal cancer screening in Canada.

Colorectal cancer screening in average risk individuals

Colorectal cancer is the third leading type of cancer, and the second leading cause of cancer-related death in the United States. Prevention of colorectal cancer should be achievable by screening programs that detect adenomas in asymptomatic patients and lead to their removal. In this manuscript, we review the major screening modalities, the advantages and disadvantages of each approach, the data supporting their use, and various issues affecting the implementation of each test. Screening guidelines will be reviewed, and future techniques for colorectal cancer screening examined.