National audit of the sensitivity of double-contrast barium enema for colorectal carcinoma, using control charts

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

BACKGROUND

Computed tomographic colonography (CTC) is a relatively new diagnostic test that may be superior to existing alternatives to investigate the large bowel.

OBJECTIVES

To compare the diagnostic efficacy, acceptability, safety and cost-effectiveness of CTC with barium enema (BE) or colonoscopy.

DESIGN

Parallel randomised trials: BE compared with CTC and colonoscopy compared with CTC (randomisation 2 : 1, respectively).

SETTING

A total of 21 NHS hospitals.

PARTICIPANTS

Patients aged ≥ 55 years with symptoms suggestive of colorectal cancer (CRC).

INTERVENTIONS

CTC, BE and colonoscopy.

MAIN OUTCOME MEASURES

For the trial of CTC compared with BE, the primary outcome was the detection rate of CRC and large polyps (≥ 10 mm), with the proportion of patients referred for additional colonic investigation as a secondary outcome. For the trial of CTC compared with colonoscopy, the primary outcome was the proportion of patients referred for additional colonic investigation, with the detection rate of CRC and large polyps as a secondary outcome. Secondary outcomes for both trials were miss rates for cancer (via registry data), all-cause mortality, serious adverse events, patient acceptability, extracolonic pathology and cost-effectiveness.

RESULTS

A total of 8484 patients were registered and 5384 were randomised and analysed (BE trial: 2527 BE, 1277 CTC; colonoscopy trial: 1047 colonoscopy, 533 CTC). Detection rates in the BE trial were 7.3% (93/1277) for CTC, compared with 5.6% (141/2527) for BE (p = 0.0390). The difference was due to better detection of large polyps by CTC (3.6% vs. 2.2%; p = 0.0098), with no significant difference for cancer (3.7% vs. 3.4%; p = 0.66). Significantly more patients having CTC underwent additional investigation (23.5% vs. 18.3%; p = 0.0003). At the 3-year follow-up, the miss rate for CRC was 6.7% for CTC (three missed cancers) and 14.1% for BE (12 missed cancers). Significantly more patients randomised to CTC than to colonoscopy underwent additional investigation (30% vs. 8.2%; p < 0.0001). There was no significant difference in detection rates for cancer or large polyps (10.7% for CTC vs. 11.4% for colonoscopy; p = 0.69), with no difference when cancers (p = 0.94) and large polyps (p = 0.53) were analysed separately. At the 3-year follow-up, the miss rate for cancer was nil for colonoscopy and 3.4% for CTC (one missed cancer). Adverse events were uncommon for all procedures. In 1042 of 1748 (59.6%) CTC examinations, at least one extracolonic finding was reported, and this proportion increased with age (p < 0.0001). A total of 149 patients (8.5%) were subsequently investigated, and extracolonic neoplasia was diagnosed in 79 patients (4.5%) and malignancy in 29 (1.7%). In the short term, CTC was significantly more acceptable to patients than BE or colonoscopy. Total costs for CTC and colonoscopy were finely balanced, but CTC was associated with higher health-care costs than BE. The cost per large polyp or cancer detected was £4235 (95% confidence interval £395 to £9656).

CONCLUSIONS

CTC is superior to BE for detection of cancers and large polyps in symptomatic patients. CTC and colonoscopy detect a similar proportion of large polyps and cancers and their costs are also similar. CTC precipitates significantly more additional investigations than either BE or colonoscopy, and evidence-based referral criteria are needed. Further work is recommended to clarify the extent to which patients initially referred for colonoscopy or BE undergo subsequent abdominopelvic imaging, for example by computed tomography, which will have a significant impact on health economic estimates.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN95152621.

Exploring variations in childhood stunting in Nigeria using league table, control chart and spatial analysis

BACKGROUND

Stunting, linear growth retardation is the best measure of child health inequalities as it captures multiple dimensions of children's health, development and environment where they live. The developmental priorities and socially acceptable health norms and practices in various regions and states within Nigeria remains disaggregated and with this, comes the challenge of being able to ascertain which of the regions and states identifies with either high or low childhood stunting to further investigate the risk factors and make recommendations for action oriented policy decisions.

METHODS

We used data from the birth histories included in the 2008 Nigeria Demographic and Health Survey (DHS) to estimate childhood stunting. Stunting was defined as height for age below minus two standard deviations from the median height for age of the standard World Health Organization reference population. We plotted control charts of the proportion of childhood stunting for the 37 states (including federal capital, Abuja) in Nigeria. The Local Indicators of Spatial Association (LISA) were used as a measure of the overall clustering and is assessed by a test of a null hypothesis.

RESULTS

Childhood stunting is high in Nigeria with an average of about 39%. The percentage of children with stunting ranged from 11.5% in Anambra state to as high as 60% in Kebbi State. Ranking of states with respect to childhood stunting is as follows: Anambra and Lagos states had the least numbers with 11.5% and 16.8% respectively while Yobe, Zamfara, Katsina, Plateau and Kebbi had the highest (with more than 50% of their under-fives having stunted growth).

CONCLUSIONS

Childhood stunting is high in Nigeria and varied significantly across the states. The northern states have a higher proportion than the southern states. There is an urgent need for studies to explore factors that may be responsible for these special cause variations in childhood stunting in Nigeria.

Computed tomographic colonography versus barium enema for diagnosis of colorectal cancer or large polyps in symptomatic patients (SIGGAR): a multicentre randomised trial

BACKGROUND

Barium enema (BE) is widely available for diagnosis of colorectal cancer despite concerns about its accuracy and acceptability. Computed tomographic colonography (CTC) might be a more sensitive and acceptable alternative. We aimed to compare CTC and BE for diagnosis of colorectal cancer or large polyps in symptomatic patients in clinical practice.

METHODS

This pragmatic multicentre randomised trial recruited patients with symptoms suggestive of colorectal cancer from 21 UK hospitals. Eligible patients were aged 55 years or older and regarded by their referring clinician as suitable for radiological investigation of the colon. Patients were randomly assigned (2:1) to BE or CTC by computer-generated random numbers, in blocks of six, stratified by trial centre and sex. We analysed the primary outcome-diagnosis of colorectal cancer or large (≥10 mm) polyps-by intention to treat. The trial is an International Standard Randomised Controlled Trial, number 95152621.

FINDINGS

3838 patients were randomly assigned to receive either BE (n=2553) or CTC (n=1285). 34 patients withdrew consent, leaving for analysis 2527 assigned to BE and 1277 assigned to CTC. The detection rate of colorectal cancer or large polyps was significantly higher in patients assigned to CTC than in those assigned to BE (93 [7.3%] of 1277 vs 141 [5.6%] of 2527, relative risk 1.31, 95% CI 1.01-1.68; p=0.0390). CTC missed three of 45 colorectal cancers and BE missed 12 of 85. The rate of additional colonic investigation was higher after CTC than after BE (283 [23.5%] of 1206 CTC patients had additional investigation vs 422 [18.3%] of 2300 BE patients; p=0.0003), due mainly to a higher polyp detection rate. Serious adverse events were rare.

INTERPRETATION

CTC is a more sensitive test than BE. Our results suggest that CTC should be the preferred radiological test for patients with symptoms suggestive of colorectal cancer.

FUNDING

NIHR Health Technology Assessment Programme, NIHR Biomedical Research Centres funding scheme, Cancer Research UK, EPSRC Multidisciplinary Assessment of Technology Centre for Healthcare, and NIHR Collaborations for Leadership in Applied Health Research and Care.

[Korean guidelines for colorectal cancer screening and polyp detection]

Colorectal cancer is the second most common cancer in males and the fourth most common in females in Korea. Since the most of colorectal cancer occur through the prolonged transformation of adenomas into carcinomas, early detection and removal of colorectal adenomas are one of the most effective methods to prevent colorectal cancer. Considering the increasing incidence of colorectal cancer and polyps in Korea, it is very important to establish Korean guideline for colorectal cancer screening and polyp detection. Korean Multi-Society Take Force developed the guidelines with evidence-based methods. Parts of the statements drawn by systematic reviews and meta-analyses. Herein we discussed the epidemiology of colorectal cancers and adenomas in Korea, optimal screening methods for colorectal cancer, and detection for adenomas including fecal occult blood tests, radiologic tests, and endoscopic examinations.

Comparison between CT colonography and double-contrast barium enema for colonic evaluation in patients with renal insufficiency

Objective

To compare the CT colonography (CTC) and double-contrast barium enema (DCBE) for colonic evaluation in patients with renal insufficiency.

Materials and Methods

Two sequential groups of consecutive patients with renal insufficiency who had a similar risk for colorectal cancer, were examined by DCBE (n = 182; mean ± SD in age, 51 ± 6.4 years) and CTC (n = 176; 50 ± 6.7 years), respectively. CTC was performed after colon cleansing with 250-mL magnesium citrate (n = 87) or 4-L polyethylene glycol (n = 89) and fecal tagging. DCBE was performed after preparation with 250-mL magnesium citrate. Patients with colonic polyps/masses of ≥ 6 mm were subsequently recommended to undergo a colonoscopy. Diagnostic yield and positive predictive value (PPV) for colonic polyps/masses, examination quality, and examination-related serum electrolyte change were retrospectively compared between the two groups.

Results

Both the CTC and DCBE were positive for colonic polyps/masses in 28 (16%) of 176 and 11 (6%) of 182 patients, respectively (p = 0.004). Among patients with positive findings, 17 CTC and six DCBE patients subsequently underwent a colonoscopy and yielded a PPV of 88% (15 of 17 patients) and 50% (3 of 6 patients), respectively (p = 0.089). Thirteen patients with adenomatous lesions were detected in the CTC group (adenocarcinoma [n = 1], advanced adenoma [n = 6], and non-advanced adenoma [n = 6]), as compared with two patients (each with adenocarcinoma and advanced adenoma) in the DCBE group (p = 0.003). Six (3%) of 176 CTC and 16 (9%) of 182 DCBE examinations deemed to be inadequate (p = 0.046). Electrolyte changes were similar in the two groups.

Conclusion

In patients with renal insufficiency, CTC has a higher diagnostic yield and a marginally higher PPV for detecting colorectal neoplasia, despite a similar diagnostic yield for adenocarcinoma, and a lower rate of inadequate examinations as compared with DCBE.

Korean guidelines for colorectal cancer screening and polyp detection

Now colorectal cancer is the second most common cancer in males and the fourth most common cancer in females in Korea. Since most of colorectal cancers occur after the prolonged transformation of adenomas into carcinomas, early detection and removal of colorectal adenomas are one of the most effective methods to prevent colorectal cancer. Considering the increasing incidence of colorectal cancer and polyps in Korea, it is very important to establish Korean guideline for colorectal cancer screening and polyp detection. The guideline was developed by the Korean Multi-Society Take Force and we tried to establish the guideline by evidence-based methods. Parts of the statements were draw by systematic reviews and meta-analyses. Herein we discussed epidemiology of colorectal cancers and adenomas in Korea and optimal methods for screening of colorectal cancer and detection of adenomas including fecal occult blood tests, radiologic tests, and endoscopic examinations.

Exploring variations in under-5 mortality in Nigeria using league table, control chart and spatial analysis

BACKGROUND

Under-5 mortality rate (U5MR) is the probability of a child born in a specific year or period dying before reaching the age of 5. Nigeria has a high rate of U5MR and accounts for a significant proportion of the high U5MR in sub-Sahara Africa. There are differences in health and social practice in the different states in Nigeria, coupled with the differences in developmental priorities of each State government. There is therefore the need to identify the states with high and low U5MR, to further explore the risk factors and make recommendations for planning. This study investigates variation in U5MR in Nigeria using Shewhart's theory of variation and control charts.

METHODS

We used data from the birth histories included in the 2008 Nigerian Demographic and Health Survey to estimate U5MR using a synthetic cohort life table. We plotted control charts of the proportion of under-5 mortality for the 37 states (included federal capital Abuja) in Nigeria. The Local Indicators of Spatial Association was used as a measure of the overall clustering and is assessed by a test of a null hypothesis.

RESULTS

On average, more than 1 in every 10 children born in Nigeria (159 per 1000 live births) does not survive to their fifth birthday. Kwara and Osun states had the lowest U5MR (less than 60 per 1000 live births), while Jigawa, Kano, Sokoto, Niger and Adamawa states had the highest U5MR (more than 200 per 1000 live births). There is a wide variation in the U5MR between the 37 states. The funnel plot identifies 27 (73%) states within the 99% control limits indicating common-cause variation. Four states were above the upper control limit (higher than the average) and six states were below the lower control limit (lower than the average), indicating special-cause variation.

CONCLUSIONS

U5MR is high in Nigeria; the rates are in three digits. There is a wide variation in the U5MR in Nigeria, with 27% showing evidence of special-cause variation which merits further investigation to identify possible causes. However, the vast majority of states (73%) are consistent with common-cause variation.

Clinical audit-ESR perspective

This paper provides a comprehensive outline of the audit process advocated for clinical radiologists and clinical radiology departments. The philosophy discussed is equally appropriate for interventional and diagnostic radiologists.

Considering double contrast barium enema and its demise: a case for systematic videorecording of colonoscopy

Double contrast barium enema (DCBE) continues its decline. One area where DCBE and CT colonography surpass colonoscopy is in documentation. Colonoscopy could improve documentation by systematic videorecording of examinations (or at least of the withdrawal portions). Investigation of the impact of systematic videorecording of colonoscopy on quality, cost, and medical-legal risk is warranted.

Rates of new or missed colorectal cancer after barium enema and their risk factors: a population-based study

OBJECTIVE

Double-contrast barium enema (DCBE) is widely used in clinical practice to detect colorectal cancer (CRC). Our objective was to evaluate the rate of new or missed CRC following DCBE and the associated risk factors in a population-based study.

METHODS

All patients (> or =20 yr old) with a new diagnosis of CRC between April 1, 1997, and March 31, 2004, in Ontario were identified. Data were extracted from the Ontario Health Insurance Program, the Canadian Institute for Health Information, the Registered Persons Database and the Ontario Cancer Registry. Patients who had a DCBE examination 36 months prior to the diagnosis of CRC were divided into two groups: detected cancers (DCBE within 6 months prior to diagnosis) and new or missed cancers (DCBE 6-36 months prior to diagnosis). Multivariate analysis was used to evaluate factors associated with new or missed CRC.

RESULTS

We identified 13,849 patients who had a DCBE 36 months prior to the diagnosis of CRC. The overall rate of new or missed cancers following DCBE was 22.4%. Independent risk factors for new or missed cancers were older age, female sex, previous abdominal or pelvic surgery, diverticular disease, right-sided CRC, and having the DCBE in an office setting.

CONCLUSIONS

Physicians who use DCBE to evaluate the colon must inform their patients that if a cancer is present, there is an approximately one in five chance that it will be missed. Given the recent endorsement of CT colonography by the U.S. Multi-Society Task Force on Colorectal Cancer as an option for CRC screening, it may be time to reconsider the use of DCBE to detect CRC.

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

In the United States, colorectal cancer (CRC) is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. CRC largely can be prevented by the detection and removal of adenomatous polyps, and survival is significantly better when CRC is diagnosed while still localized. In 2006 to 2007, the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology came together to develop consensus guidelines for the detection of adenomatous polyps and CRC in asymptomatic average-risk adults. In this update of each organization's guidelines, screening tests are grouped into those that primarily detect cancer early and those that can detect cancer early and also can detect adenomatous polyps, thus providing a greater potential for prevention through polypectomy. When possible, clinicians should make patients aware of the full range of screening options, but at a minimum they should be prepared to offer patients a choice between a screening test that primarily is effective at early cancer detection and a screening test that is effective at both early cancer detection and cancer prevention through the detection and removal of polyps. It is the strong opinion of these 3 organizations that colon cancer prevention should be the primary goal of screening.

Critical analysis of the performance of double-contrast barium enema for detecting colorectal polyps > or = 6 mm in the era of CT colonography

OBJECTIVE

The purpose of our study was to perform a meta-analysis comparing the performance of double-contrast barium enema (DCBE) with CT colonography (CTC) for the detection of colorectal polyps > or = 6 mm using endoscopy as the gold standard.

MATERIALS AND METHODS

Prospective DCBE and CTC studies were identified. Percentages of polyps and of patients with polyps > or = 10 mm and 6-9 mm were abstracted. The performance of DCBE versus CTC was determined by separately evaluating each technique's performance versus that of endoscopy, and contrasting the techniques. The I-squared statistic and Fisher's exact test were used for heterogeneity, the Cochran-Mantel-Haenszel and the Kruskal-Wallis tests for correlation, and the A(z) test for comparing pooled weighted estimates of performance.

RESULTS

Eleven studies of DCBE (5,995 patients, 1,548 polyps) and 30 studies of CTC (6,573 patients, 2,348 polyps) fulfilled inclusion criteria. For polyps > or = 10 mm, a 0.121-per-patient sensitivity difference favored CTC (p < 0.0001; DCBE, 0.702 [95% CI, 0.687-0.715]; CTC, 0.823 [0.809-0.836]). For polyps > or = 10 mm, a 0.031-per-polyp sensitivity difference favored CTC (p < 0.0001; DCBE, 0.715 [0.703-0.726]; CTC, 0.746 [0.735-0.757]). For polyps > or = 10 mm, a specificity difference of 0.104 favored CTC (p = 0.001; DCBE, 0.850 [0.847-0.855]; CTC, 0.954 [0.952-0.955]). DCBE was also significantly less sensitive for 6- to 9-mm polyps (p < 0.001).

CONCLUSION

DCBE has statistically lower sensitivity and specificity than CTC for detecting colorectal polyps > or = 6 mm.

CT colonography: interpretative performance in a non-academic environment

AIM

To investigate interpretative accuracy and reporting time for radiologists performing computed tomography (CT) colonography in day-to-day non-academic clinical practice.

MATERIALS AND METHODS

Thirteen radiologists from seven centres, who were reporting CT colonography in non-academic daily clinical practice, interpreted a dataset of 15 colonoscopically validated cases in a controlled environment. Ten cases had either a cancer or polyp >10mm; one case had a medium polyp and four were normal. Correct case categorization and interpretation times were compared using analysis of variance to aggregated results obtained from both experienced observers and observers recently trained using 50 cases, working in an academic environment. The effect of experience was determined using Spearman's rank correlation.

RESULTS

Individual accuracy was highly variable, range 53% (95% CI 27-79%) to 93% (95% CI 68-100%). Mean accuracy overall was significantly inferior to experienced radiologists (mean 75 versus 88%, p=0.04) but not significantly different from recently trained radiologists (p=0.48). Interpretation time was not significantly different to experienced readers (mean 12.4 min versus 11.7, p=0.74), but shorter than recently trained radiologists (p=0.05). There was a significant, positive, linear correlation between prior experience and accuracy (p<0.001) with no plateau.

CONCLUSION

Accuracy for sub-specialist radiologists working in a non-academic environment is, on average, equivalent to radiologists trained using 50 cases. However, there is wide variability in individual performance, which generally falls short of the average performance suggested by meta-analysis of published data. Experience improves accuracy, but alone is insufficient to determine competence.