Double-contrast barium enema examination and colorectal cancer: a plea for radiologic screening

Progress of colorectal cancer screening in United States: Past achievements and future challenges

The United States has seen progress with colorectal cancer with both falling incidence and mortality rates. Factoring into this decline, the significance of early detection and removal of precancerous lesions through screening must be underscored. With the advancement of screening modalities, attention has been directed towards optimizing the quality of screening and detecting adenomas. Colorectal cancer screening has been a major agenda item for national gastroenterology societies, culminating in a major victory with passage of the Balanced Budget Act that allowed for Medicare coverage of colorectal cancer screening. Colonoscopy as the primary screening modality was solidified in the 1990s after landmark studies demonstrated its superiority over modalities for detecting precancerous polyps. Despite progress, colorectal cancer screening disparities between race and gender continue to exist. Legislative efforts are on-going and include the SCREEN Act and Dent Act that aim to further improve access to screening. The National Colorectal Cancer Roundtable has launched colorectal cancer screening initiatives targeting at risk populations. Today, the current goal of these initiatives is to reach colorectal screening rate of 80% of eligible patients by 2018. With these initiatives, efforts to narrow the gaps in screening disparities and lower overall mortality have been prioritized and continued by the medical community. This review article details colorectal cancer screening progress to date and highlights major studies and initiatives that have solidified its success in the United States.

History, evolution, and current status of radiologic imaging tests for colorectal cancer screening

Colorectal cancer screening is thought to be an effective tool with which to reduce the mortality from colorectal cancer through early detection and removal of colonic adenomas and early colon cancers. In this article, we review the history, evolution, and current status of imaging tests of the colon-including single-contrast barium enema, double-contrast barium enema, computed tomographic (CT) colonography, and magnetic resonance (MR) colonography-for colorectal cancer screening. Despite its documented value in the detection of colonic polyps, the double-contrast barium enema has largely disappeared as a screening test because it is widely perceived as a labor-intensive, time-consuming, and technically demanding procedure. In the past decade, the barium enema has been supplanted by CT colonography as the major imaging test in colorectal cancer screening in the United States, with MR colonography emerging as another viable option in Europe. Although MR colonography does not require ionizing radiation, the radiation dose for CT colonography has decreased substantially, and regular screening with this technique has a high benefit-to-risk ratio. In recent years, CT colonography has been validated as an effective tool for use in colorectal cancer screening that is increasingly being disseminated.

Colorectal cancer screening by double contrast barium enema in Thai people

PURPOSE

The incidence of colorectal cancer (CRC) has been increasing in Asian countries including Thailand. Double contrast barium enema (DCBE) is one of the investigation tools used in CRC screening. This study aimed to determine the incidence of colorectal neoplasm detected at screening by DCBE in Thai people.

METHODS

The computerized radiology database of screening DCBE in Thai adults between June 2009 and October 2011 at the Faculty of Medicine, Siriraj Hospital, was reviewed. DCBE examination performed in a surveillance program after curative CRC resection or the removal of colorectal polyps was also considered as a screening DCBE.

RESULTS

A total of 819 screening DCBEs performed during this 28-month period were analyzed. The mean age of patients was 59.8 ∓ 13.6 years. Of the total, 467 (57%) were male. A family history of CRC and a previous history of curative CRC resection or polyp removal were noted in 34 patients (4%) and 124 patients (15%), respectively. A total of 31 patients (3.8%; 95%CI = 2.7%-5.3%) were reported to have colorectal polyp or mass demonstrated on DCBE. Of these, follow-up endoscopy was performed in 20 cases (65%). According to pathological results, the incidence of advanced adenoma and CRC detected at screening DCBE was 0.7% (95%CI = 0.3%-1.6%; n=6) and 0.4% (95%CI = 0.1%-1.1%; n=3), respectively.

CONCLUSIONS

The screening DCBE performed in Thai adults had a diagnostic yield of 0.7% for advanced adenoma and 0.4% for CRC.

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.

Update on Colorectal Cancer Imaging

Colorectal cancer remains a leading cancer killer worldwide. The disease is both curable and preventable, and yet the importance of widespread screening is only now starting to be appreciated. This article reviews the variety of diagnostic tests, imaging procedures and endoscopic examinations available to detect colorectal cancer and polyps in their early stage and also presents details on various screening options. The critical role of the radiologist is elaborated on including accurate assessment of the tumor extent within the bowel wall and beyond and the detection of lymph node and distant metastases. Staging with CT, MR imaging, endorectal ultrasound, and positron emission tomography are of paramount importance in determining the most appropriate therapy and the risk of tumor recurrence and overall prognosis.

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Optimization of Scanning Parameters for Multi-slice CT Colonography: Experiments with Synthetic and Animal Phantoms

AIM

To determine the optimal collimation, pitch, tube current and reconstruction interval for multi-slice computed tomography (CT) colonography with regard to attaining satisfactory image quality while minimizing patient radiation dose.

MATERIALS AND METHODS

Multi-slice CT was performed on plastic, excised pig colon and whole pig phantoms to determine optimal settings. Performance was judged by detection of simulated polyps and statistical measures of the image parameters. Fat and muscle conspicuity was measured from images of dual tube-current prone/supine patient data to derive a measure of tube current effects on tissue contrast.

RESULTS

A collimation of 4 x 2.5 mm was sufficient for detection of polyps 4 mm and larger, provided that a reconstruction interval of 1.25 mm was used. A pitch of 1.5 allowed faster scanning and reduced radiation dose without resulting in a loss of important information, i.e. detection of small polyps, when compared with a pitch of 0.75. Tube current and proportional radiation dose could be lowered substantially without deleterious effects on the detection of the air-mucosal interface, however, increased image noise substantially reduced conspicuity of different tissues.

CONCLUSION

An optimal image acquisition set-up of 4 x 2.5 mm collimation, reconstruction interval of 1.25 mm, pitch of 1.5 and dual prone/supine scan of 40/100 mA tube current is proposed for our institution for scanning symptomatic patients. Indications are that where CT colonography is used for colonic polyp screening in non-symptomatic patients, a 40 mA tube current could prove satisfactory for both scans.

Acceptance by patients of multidetector CT colonography compared with barium enema examinations, flexible sigmoidoscopy, and colonoscopy

OBJECTIVE

The purpose of this study was to compare patient acceptance of multidetector CT colonography, total colonoscopy, flexible sigmoidoscopy, and double-contrast barium enema to ascertain any overall preference. SUBJECTS AND METHODS. One hundred sixty-eight patients underwent CT colonography followed by either flexible sigmoidoscopy (n = 59) or colonoscopy (n = 109). A 25-point questionnaire with principal components relating to satisfaction, worry, and physical discomfort was administered after CT colonography and after endoscopy, and a follow-up questionnaire was administered 1 week after the procedures. Questionnaires were also completed by 140 patients undergoing double-contrast barium enema examinations. Responses were compared using Wilcoxon's matched pairs test and the Mann-Whitney test.

RESULTS

Overall satisfaction was greater with colonoscopy (p = 0.01), but CT colonography caused less discomfort (p = 0.002), was better tolerated (p = 0.005), and was the preferred follow-up investigation of those expressing a preference (p = 0.003). Compared with flexible sigmoidoscopy, CT colonography caused less pain (p = 0.004), was more acceptable (p = 0.04), and was preferred as the follow-up investigation (p < 0.001). Tolerance of colonoscopy was significantly less in women (p = 0.03), but such was not the case for CT colonography (p = 0.58). Patients undergoing CT colonography were less worried (p < 0.001), were more satisfied (p = 0.001), and suffered less discomfort (p < 0.001) than those having barium enema.

CONCLUSION

Patients' experiences with barium enema examinations were significantly worse than with any other test. Although patients were most satisfied with colonoscopy, they reported more pain during both colonoscopy and sigmoidoscopy than during CT colonography, and they also found CT more acceptable. In patients expressing a preference, CT colonography was the preferred follow-up investigation.

Colorectal cancer screening with double-contrast barium enema: a national survey of diagnostic radiologists

OBJECTIVE

This article describes diagnostic radiologists' colorectal cancer screening activities and beliefs about screening effectiveness and future capacity for screening with double-contrast barium enema, and compares radiologists' opinions about colorectal cancer screening with those of primary care physicians.

MATERIALS AND METHODS

We surveyed a nationally representative sample of diagnostic radiologists. Of 381 eligible radiologists, 312 (82%) responded. Descriptive statistics and chi-square tests were used to assess radiologists' opinions about double-contrast barium enema volume and capacity and to compare radiologists' beliefs about colorectal cancer screening with those of primary care physicians. Logistic regression was used to identify characteristics of radiologists who receive referrals for or perform a higher volume of screening double-contrast barium enema and of those who expect the volume of double-contrast barium enemas to increase.

RESULTS

Seventy-five percent of radiologists said that double-contrast barium enema is a "very effective" colorectal cancer screening procedure compared with 33% of primary care physicians. Although 86% of radiologists reported performing one or more screening double-contrast barium enema procedures during a typical month, only 27% indicated that they did so 11 or more times. Fifteen percent of radiologists said that their double-contrast barium enema volume had increased over the past 3 years, and 50% expect an increase over the next 3 years. Only 8% said that the capacity of facilities and personnel to meet the demand for double-contrast barium enemas in their geographic area of practice is inadequate. Geographic region and belief in double-contrast barium enema efficacy were predictors of double-contrast barium enema volume and referrals.

CONCLUSION

Most diagnostic radiologists perform colorectal cancer screening with double-contrast barium enema, but procedure volumes are modest. Because primary care physicians view double-contrast barium enema less positively than do radiologists, radiologists' expectations for an increased volume of double-contrast barium enemas over the next few years may not be realized.