Alex Ghanouni

Patient acceptability of CT colonography compared with double contrast barium enema: results from a multicentre randomised controlled trial of symptomatic patients

ObjectivesTo determine patient acceptability of barium enema (BE) or CT colonography (CTC).MethodsAfter ethical approval, 921 consenting patients with symptoms suggestive of colorectal cancer who had been randomly assigned and completed either BE (N = 606) or CTC (N = 315) received a questionnaire to assess experience of the clinical episode including bowel preparation, procedure and complications. Satisfaction, worry and physical discomfort were assessed using an adapted version of a validated acceptability scale. Non-parametric methods assessed differences between the randomised tests and the effect of patient characteristics.ResultsPatients undergoing BE were significantly less satisfied (median 61, interquartile range [IQR] 54–67 vs. median 64, IQR 56–69; p = 0.003) and experienced more physical discomfort (median 40, IQR 29–52 vs. median 35.5, IQR 25–47; p < 0.001) than those undergoing CTC. Post-test, BE patients were significantly more likely to experience ‘abdominal pain/cramps’ (68% vs. 57%; p = 0.007), ‘soreness’ (57% vs. 37%; p < 0.001), ‘nausea/vomiting’ (16% vs. 8%; p = 0.009), ‘soiling’ (31% vs. 23%; p = 0.034) and ‘wind’ (92% vs. 84%; p = 0.001) and in the case of ‘wind’ to also rate it as severe (27% vs. 15%; p < 0.001).ConclusionCTC is associated with significant improvements in patient experience. These data support the case for CTC to replace BE.

Detection of Extracolonic Pathologic Findings with CT Colonography: A Discrete Choice Experiment of Perceived Benefits versus Harms

PURPOSE To determine the maximum rate of false-positive diagnoses that patients and health care professionals were willing to accept in exchange for detection of extracolonic malignancy by using computed tomographic (CT) colonography for colorectal cancer screening. MATERIALS AND METHODS After obtaining ethical approval and informed consent, 52 patients and 50 health care professionals undertook two discrete choice experiments where they chose between unrestricted CT colonography that examined intra- and extracolonic organs or CT colonography restricted to the colon, across different scenarios. The first experiment detected one extracolonic malignancy per 600 cases with a false-positive rate varying across scenarios from 0% to 99.8%. One experiment examined radiologic follow-up generated by false-positive diagnoses while the other examined invasive follow-up. Intracolonic performance was identical for both tests. The median tipping point (maximum acceptable false-positive rate for extracolonic findings) was calculated overall and for both groups by bootstrap analysis. RESULTS The median tipping point for radiologic follow-up occurred at a false-positive rate greater than 99.8% (interquartile ratio [IQR], 10 to >99.8%). Participants would tolerate at least a 99.8% rate of unnecessary radiologic tests to detect an additional extracolonic malignancy. The median tipping-point for invasive follow-up occurred at a false-positive rate of 10% (IQR, 2 to >99.8%). Tipping points were significantly higher for patients than for health care professionals for both experiments (>99.8 vs 40% for radiologic follow-up and >99.8 vs 5% for invasive follow-up, both P < .001). CONCLUSION Patients and health care professionals are willing to tolerate high rates of false-positive diagnoses with CT colonography in exchange for diagnosis of extracolonic malignancy. The actual specificity of screening CT colonography for extracolonic findings in clinical practice is likely to be highly acceptable to both patients and health care professionals. Online supplemental material is available for this article.

Public perceptions and preferences for CT colonography or colonoscopy in colorectal cancer screening

OBJECTIVES To examine public perceptions of and preferences for colonoscopy vs. CT colonography (CTC) as technologies for colorectal cancer (CRC) screening. METHODS Six discussion groups were carried out with 30 adults aged 49-60 years (60% female). Information about different aspects of the tests (e.g. sensitivity, practical issues) was presented sequentially using a semi-structured, step-by-step topic guide. Discussions were recorded and analyzed using framework analysis. RESULTS CTC was favored on the parameters of invasiveness, extra-colonic evaluation and interference with daily life, whereas sensitivity, avoiding false-positives and the capacity to remove polyps immediately were perceived to be important advantages of colonoscopy. Ultimately, there was no strong preference for either test: with 46% preferring colonoscopy vs. 42% for CTC. CONCLUSION With comprehensive information, colonoscopy and CTC were seen as having different advantages and disadvantages, yielding no clear preferences between the two. The sensitivity of colonoscopy was a decisive factor for some people, but the lower invasiveness of CTC was seen as an asset in the screening context. PRACTICE IMPLICATIONS CTC may be an acceptable alternative to colonoscopy in CRC screening. Healthcare professionals working in the screening context should be sensitive to the range of characteristics that can determine preferences for CRC screening tests.

Patients' & Healthcare Professionals' Values Regarding True- & False-Positive Diagnosis when Colorectal Cancer Screening by CT Colonography: Discrete Choice Experiment

Purpose To establish the relative weighting given by patients and healthcare professionals to gains in diagnostic sensitivity versus loss of specificity when using CT colonography (CTC) for colorectal cancer screening. Materials and Methods Following ethical approval and informed consent, 75 patients and 50 healthcare professionals undertook a discrete choice experiment in which they chose between “standard” CTC and “enhanced” CTC that raised diagnostic sensitivity 10% for either cancer or polyps in exchange for varying levels of specificity. We established the relative increase in false-positive diagnoses participants traded for an increase in true-positive diagnoses. Results Data from 122 participants were analysed. There were 30 (25%) non-traders for the cancer scenario and 20 (16%) for the polyp scenario. For cancer, the 10% gain in sensitivity was traded up to a median 45% (IQR 25 to >85) drop in specificity, equating to 2250 (IQR 1250 to >4250) additional false-positives per additional true-positive cancer, at 0.2% prevalence. For polyps, the figure was 15% (IQR 7.5 to 55), equating to 6 (IQR 3 to 22) additional false-positives per additional true-positive polyp, at 25% prevalence. Tipping points were significantly higher for patients than professionals for both cancer (85 vs 25, p<0.001) and polyps (55 vs 15, p<0.001). Patients were willing to pay significantly more for increased sensitivity for cancer (p = 0.021). Conclusion When screening for colorectal cancer, patients and professionals believe gains in true-positive diagnoses are worth much more than the negative consequences of a corresponding rise in false-positives. Evaluation of screening tests should account for this.

Public preferences for colorectal cancer screening tests: a review of conjoint analysis studies

A wide range of screening technologies is available for colorectal cancer screening. There is demand to discover public preferences for these tests on the rationale that tailoring screening to preferences may improve uptake. This review describes a type of study (conjoint analysis) used to assess people’s preferences for colorectal cancer screening tests and critically evaluates research quality using a recently published set of guidelines. Most primary studies assessed preferences for colonoscopy and fecal occult blood testing but newer technologies (e.g., capsule endoscopy) have not yet been evaluated. Although studies often adhered to guidelines, there was limited correspondence between stated preferences and actual screening behavior. Future research should investigate how studies can go beyond the guidelines in order to improve this and also explore how test preferences may differ by important population subgroups.

Patient factors associated with non-attendance at colonoscopy after a positive screening faecal occult blood test

Background Screening participants with abnormal faecal occult blood test results who do not attend further testing are at high risk of colorectal cancer, yet little is known about their reasons for non-attendance. Methods We conducted a medical record review of 170 patients from two English Bowel Cancer Screening Programme centres who had abnormal guaiac faecal occult blood test screening tests between November 2011 and April 2013 but did not undergo colonoscopy. Using information from patient records, we coded and categorized reasons for non-attendance. Results Of the 170 patients, 82 were eligible for review, of whom 66 had at least one recorded reason for lack of colonoscopy follow-up. Reasons fell into seven main categories: (i) other commitments, (ii) unwillingness to have the test, (iii) a feeling that the faecal occult blood test result was a false positive, (iv) another health issue taking priority, (v) failing to complete bowel preparation, (vi) practical barriers (e.g. lack of transport), and (vii) having had or planning colonoscopy elsewhere. The most common single reasons were unwillingness to have a colonoscopy and being away. Conclusions We identify a range of apparent reasons for colonoscopy non-attendance after a positive faecal occult blood test screening. Education regarding the interpretation of guaiac faecal occult blood test findings, offer of alternative confirmatory test options, and flexibility in the timing or location of subsequent testing might decrease non-attendance of diagnostic testing following positive faecal occult blood test.

Quantifying public preferences for different bowel preparation options prior to screening CT colonography: a discrete choice experiment

Objectives CT colonography (CTC) may be an acceptable test for colorectal cancer screening but bowel preparation can be a barrier to uptake. This study tested the hypothesis that prospective screening invitees would prefer full-laxative preparation with higher sensitivity and specificity for polyps, despite greater burden, over less burdensome reduced-laxative or non-laxative alternatives with lower sensitivity and specificity. Design Discrete choice experiment. Setting Online, web-based survey. Participants 2819 adults (45–54 years) from the UK responded to an online invitation to take part in a cancer screening study. Quota sampling ensured that the sample reflected key demographics of the target population and had no relevant bowel disease or medical qualifications. The analysis comprised 607 participants. Interventions After receiving information about screening and CTC, participants completed 3–4 choice scenarios. Scenarios showed two hypothetical forms of CTC with different permutations of three attributes: preparation, sensitivity and specificity for polyps. Primary outcome measures Participants considered the trade-offs in each scenario and stated their preferred test (or chose neither). Results Preparation and sensitivity for polyps were both significant predictors of preferences (coefficients: −3.834 to −6.346 for preparation, 0.207–0.257 for sensitivity; p<0.0005). These attributes predicted preferences to a similar extent. Realistic specificity values were non-significant (−0.002 to 0.025; p=0.953). Contrary to our hypothesis, probabilities of selecting tests were similar for realistic forms of full-laxative, reduced-laxative and non-laxative preparations (0.362–0.421). However, they were substantially higher for hypothetical improved forms of reduced-laxative or non-laxative preparations with better sensitivity for polyps (0.584–0.837). Conclusions Uptake of CTC following non-laxative or reduced-laxative preparations is unlikely to be greater than following full-laxative preparation as perceived gains from reduced burden may be diminished by reduced sensitivity. However, both attributes are important so a more sensitive form of reduced-laxative or non-laxative preparation might improve uptake substantially.

Survey of public definitions of the term ‘overdiagnosis’ in the UK

Objectives To determine how ‘overdiagnosis’ is currently conceptualised among adults in the UK in light of previous research, which has found that the term is difficult for the public to understand and awareness is low. This study aimed to add to current debates on healthcare in which overdiagnosis is a prominent issue. Design An observational, web-based survey was administered by a survey company. Setting Participants completed the survey at a time and location of their choosing. Participants 390 consenting UK adults aged 50–70 years. Quota sampling was used to achieve approximately equal numbers in three categories of education and equal numbers of men and women. Primary outcome measures Participants were asked whether they had seen or heard the term ‘overdiagnosis’. If they had, they were then invited to explain in a free-text field what they understood it to mean. If they had not previously encountered it, they were invited to say what they thought it meant. Responses were coded and interpreted using content analysis and descriptive statistics. Results Data from 390 participants were analysed. Almost a third (30.0%) of participants reported having previously encountered the term. However, their responses often indicated that they had no knowledge of its meaning. The most prevalent theme consisted of responses related to the diagnosis itself. Subthemes indicated common misconceptions, including an ‘overly negative or complicated diagnosis’, ‘false-positive diagnosis’ or ‘misdiagnosis’. Other recurring themes consisted of responses related to testing (ie, ‘too many tests’), treatment (eg, ‘overtreatment’) and patient psychology (eg, ‘overthinking’). Responses categorised as consistent with ‘overdiagnosis’ (defined as detection of a disease that would not cause symptoms or death) were notably rare (n=10; 2.6%). Conclusions Consistent with previous research, public awareness of ‘overdiagnosis’ in the UK is low and its meaning is often misunderstood or misinterpreted.

Common methods of measuring ‘informed choice’ in screening participation: Challenges and future directions

There is general agreement among public health practitioners, academics, and policymakers that people offered health screening tests should be able to make informed choices about whether to accept. Robust measures are necessary in order to gauge the extent to which informed choice is achieved in practice and whether efforts to improve it have succeeded. This review aims to add to the literature on how to improve methods of measuring informed choice. We discuss and critique commonly-used approaches and outline possible alternative methods that might address the issues identified. We explore the challenges of defining what information should be provided about screening and hence understood by service users, appraise the use of ‘thresholds’ to define e.g. positive attitudes towards screening, and describe problems inherent in conceptualising ‘informed choice’ as a single dichotomous outcome that either does or does not occur. Suggestions for future research include providing greater detail on why particular aspects of screening information were considered important, analysing knowledge and attitude measures at an ordinal or continuous level (avoiding problematic decisions about dichotomising data in order to set thresholds), and reconceptualising informed choice as a multifactorial set of outcomes, rather than a unitary one.

Information on 'Overdiagnosis' in Breast Cancer Screening on Prominent United Kingdom- and Australia-Oriented Health Websites.

Objectives Health-related websites are an important source of information for the public. Increasing public awareness of overdiagnosis and ductal carcinoma in situ (DCIS) in breast cancer screening may facilitate more informed decision-making. This study assessed the extent to which such information was included on prominent health websites oriented towards the general public, and evaluated how it was explained. Design Cross-sectional study. Setting Websites identified through Google searches in England (United Kingdom) and New South Wales (Australia) for “breast cancer screening” and further websites included based on our prior knowledge of relevant organisations. Main Outcomes Content analysis was used to determine whether information on overdiagnosis or DCIS existed on each site, how the concepts were described, and what statistics were used to quantify overdiagnosis. Results After exclusions, ten UK websites and eight Australian websites were considered relevant and evaluated. They originated from charities, health service providers, government agencies, and an independent health organisation. Most contained some information on overdiagnosis (and/or DCIS). Descriptive information was similar across websites. Among UK websites, statistical information was often based on estimates from the Independent UK Panel on Breast Cancer Screening; the most commonly provided statistic was the ratio of breast cancer deaths prevented to overdiagnosed cases (1:3). A range of other statistics was included, such as the yearly number of overdiagnosed cases and the proportion of women screened who would be overdiagnosed. Information on DCIS and statistical information was less common on the Australian websites. Conclusions Online information about overdiagnosis has become more widely available in 2015–16 compared with the limited accessibility indicated by older research. However, there may be scope to offer more information on DCIS and overdiagnosis statistics on Australian websites. Moreover, the variability in how estimates are presented across UK websites may be confusing for the general public.