False-negative barium enema in patients with sigmoid cancer and coexistent diverticula

Accuracy of Double Contrast Barium Enema and Sigmoideoscopy in the Detection of Polyps in Patients with Diverticulosis

The sensitivity between double contrast barium enema (DCBE) and sigmoideoscopy in diagnosing neoplastic lesions in the sigmoid colon was compared in patients with diverticulosis. In 52 patients with severe diverticulosis (≥15 diverticulas) the DCBE detected one out of 4 polyps found by sigmoideoscopy. In the remaining 54 patients with mild diverticulosis (<15 diverticulas) DCBE detected 7 out of 10 polyps found by sigmoideoscopy. Successful bowel preparation did not influence the outcome of the DCBE. Sigmoideoscopy was incomplete in 17 (16%) of the patients; females were more difficult to examine than males (p= 0.012), as were those with a previous pelvic operation (p= 0.032). We conclude that neither DCBE nor sigmoideoscopy alone is sufficient to detect all neoplastic lesions in the sigmoid colon in patients with sigmoid diverticulosis of the colon.

Diverticulosis and the risk of interval colorectal cancer

BACKGROUND

Diverticulosis, a prevalent condition at screening colonoscopy, has been associated with colorectal cancers that develop after a clearing colonoscopy, or interval cancers.

AIMS

To quantify the overall risk of diverticulosis in the development of interval cancers and examine this association in relevant subgroups.

METHODS

Using a linked database containing SEER tumor registry data and Medicare claims, we identified patients aged ≥69 years with colorectal cancer who underwent colonoscopy within 6 months of diagnosis. Patients with an additional colonoscopy from 36 to 6 months prior to cancer diagnosis were characterized as having interval cancers. We compared characteristics of patients with interval cancers and detected cancers according to a diagnosis of diverticulosis not associated with a colonoscopy procedure from 1991 through the date of the most recent colonoscopy in both univariate and multivariate models.

RESULTS

A previous diagnosis of diverticulosis was documented in 14,452 (26.9 %) patients with detected cancers compared to 2,905 (69.3 %) patients with interval cancers (p < 0.001); these results were consistent in multivariable analysis. Moreover, the association was found as well in the proximal colon (OR 2.88, 95 % CI 2.66, 3.12), distal colon (OR 3.56, 95 % CI 3.09, 4.11), and rectum (OR 4.07, 95 % CI 3.34, 4.95). The vast majority of diverticulosis diagnoses were without complications such as hemorrhage or diverticulitis.

CONCLUSIONS

Diverticulosis was strongly associated with interval colorectal cancers in all segments of the colon. Given its known predominance in the left colon, the findings argue against impaired visualization of lesions at colonoscopy as the only pathogenic factor.

Prevalence and predictors of interval colorectal cancers in medicare beneficiaries

BACKGROUND

After a colonoscopy that is negative for cancer, a subset of patients may be diagnosed with colorectal cancer, also termed interval cancer. The frequency and predictors have not been well studied in a population-based US cohort.

METHODS

The authors used the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database to identify 57,839 patients aged ≥ 69 years who were diagnosed with colorectal cancer between 1994 and 2005 and who underwent colonoscopy within 6 months of cancer diagnosis. Colonoscopy performed between 6 and 36 months before cancer diagnosis was a proxy for interval cancer.

RESULTS

By using the case definition, 7.2% of patients developed interval cancers. Factors that were associated with interval cancers included proximal tumor location (distal colon: multivariable odds ratio [OR], 0.42; 95% confidence interval [CI], 0.390-0.46; rectum: OR, 0.47; 95% CI, 0.42-0.53), increased comorbidity (OR, 1.89; 95% CI, 1.68 2.14 for ≥ 3 comorbidities), a previous diagnosis of diverticulosis (OR, 6.00; 95% CI, 5.57-6.46), and prior polypectomy (OR, 1.74; 95% CI, 1.62-1.87). Risk factors at the endoscopist level included a lower polypectomy rate (OR, 0.70; 95% CI, 0.63-0.78 for the highest quartile), higher colonoscopy volume (OR, 1.27; 95% CI, 1.13-1.43), and specialty other than gastroenterology (colorectal surgery: OR, 1.45; 95% CI, 1.16-1.83; general surgery: OR, 1.42; 95% CI, 1.24-1.62; internal medicine: OR, 1.38; 95% CI, 1.17-1.63; family practice: OR, 1.16; 95% CI, 1.00-1.35).

CONCLUSIONS

A significant proportion of patients developed interval colorectal cancer, particularly in the proximal colon. Contributing factors likely included both procedural and biologic factors, emphasizing the importance of meticulous examination of the mucosa.

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.

Rates of new or missed colorectal cancers after colonoscopy and their risk factors: a population-based analysis

BACKGROUND & AIMS

The rate of new or missed colorectal cancer (CRC) after colonoscopy and their risk factors in usual practice are unknown. Our objective was to evaluate the rate and risk factors in a population-based study.

METHODS

We analyzed data from the Canadian Institute for Health Information, the Ontario Health Insurance Program, and Ontario Cancer Registry for all patients (> or =20 years of age) with a new diagnosis of right-sided, transverse, splenic flexure/descending, rectal or sigmoid CRC in Ontario from April 1, 1997 to March 31, 2002, who had a colonoscopy within the 3 years before their diagnosis. Patients with new or missed cancers were those whose most recent colonoscopy was 6 to 36 months before diagnosis. We examined characteristics that might be risk factors for new or missed CRC.

RESULTS

We identified a diagnosis of CRC in 3288 (right sided), 777 (transverse), 710 (splenic flexure/descending), and 7712 (rectal or sigmoid) patients. The rates of new or missed cancers were 5.9%, 5.5%, 2.1%, and 2.3%, respectively. Independent risk factors for these cancers in men and women were older age; diverticular disease; right-sided or transverse CRC; colonoscopy by an internist or family physician; and colonoscopy in an office.

CONCLUSIONS

Because having an office colonoscopy and certain patient, procedure, and physician characteristics are independent risk factors for new or missed CRC, physicians must inform patients of the small risk (2% to 6%) of these cancers after colonoscopy. The influence of type of physician and setting on the accuracy of colonoscopy, potentially modifiable risk factors, warrants further study.

CT colonography features of sigmoid diverticular disease

OBJECTIVE

The objective of this study is to assess the sigmoid distensibility during CT colonography (CTC) in patients with diverticular disease.

METHODS

Consecutive patients without a history of pelvic radiation or neoplasms underwent 150 CTC. Three radiologists in consensus evaluated axial images for colonic distention, luminal diameters (mm), diverticula, and muscular thickening.

RESULTS

The minimum colon diameter in patients with muscular thickening was significantly smaller, irrespective of the presence of diverticula (P=.009).

CONCLUSION

Muscular thickening with diverticular disease was associated with significantly less sigmoid colon distension.

Prospective comparison of air-contrast barium enema and colonoscopy in patients with fecal occult blood: a pilot study

BACKGROUND

The utility of air-contrast barium enema and colonoscopy for evaluation of the colon has been debated. Air-contrast barium enema is less expensive and invasive than colonoscopy, but it also is less sensitive and specific. Further, although air-contrast barium enema may be less painful than colonoscopy, it often is poorly tolerated by patients. Thus, this study compared the sensitivity and the specificity of air-contrast barium enema and colonoscopy for detection of colonic lesions in patients with fecal occult blood.

METHODS

Over a 30-month period, patients with fecal occult blood were recruited. Patients underwent standard air-contrast barium enema, followed by colonoscopy 7 to 14 days later. Colonoscopists were blinded to the results of air-contrast barium enema until the colonoscopy was completed, after which the results were disclosed. If the findings were discrepant, colonoscopy was repeated.

RESULTS

A total of 100 patients were evaluated. Nine air-contrast barium enemas were reported to be inadequate, and the cecum was not intubated at colonoscopy in two patients. In the remaining patients, 5 cancers were identified (1 each cecum, transverse colon, descending colon, sigmoid colon, and rectum) by both studies. Sixty-six polypoid lesions were identified in 30 patients. Diverticula were identified in 42 patients by air-contrast barium enema and in 18 patients by colonoscopy. Air-contrast barium enema detected 3 of 36 polypoid lesions 5 mm or less in diameter, 5 of 15 adenomas 6 to 9 mm in size, and 4 of 15 adenomas 10 mm or greater in diameter (sensitivity 8%, 33%, and 27%, respectively). After excluding patients with diverticula, air-contrast barium enema detected 3 of 7 adenomas 10 mm or greater in size. Overall, 12 polypoid lesions or filling defects were identified by air-contrast barium enema that could not be verified by colonoscopy. The specificity of air-contrast barium enema for lesions 1.0 cm or greater in size was 100%; for those 6 mm or greater, it was 97%.

CONCLUSIONS

Air-contrast barium enema accurately detects colon cancer and diverticula. Its sensitivity for detection of polypoid lesions or adenomas is poor and was confounded by the presence of diverticula.

Flexible sigmoidoscopy plus air-contrast barium enema versus colonoscopy for evaluation of symptomatic patients without evidence of bleeding

One hundred forty-nine patients aged 40 years or more with symptoms suggestive of colonic disease but without evidence of gastrointestinal bleeding (absence of hematochezia, normal serum levels of hemoglobin, and at least one test negative for fecal occult blood) were randomized to undergo either initial colonoscopy or initial flexible sigmoidoscopy plus air-contrast barium enema. Patients with incomplete initial colonoscopy and certain patients with polyps seen on flexible sigmoidoscopy plus barium enema underwent the alternative procedure (barium enema or colonoscopy). The main results were as follows: First, the overall prevalence of cancer in the study was very low (0.67%). Second, initial flexible sigmoidoscopy plus barium enema detected more patients with diverticulosis than did initial colonoscopy (46% versus 31%; p = .01). Initial colonoscopy detected more persons with adenomas (p = .06) than did initial flexible sigmoidoscopy plus barium enema. Patients undergoing initial flexible sigmoidoscopy plus barium enema require the alternative procedure (24%) than were patients undergoing initial colonoscopy (6%; p = .002). Third, sensitivity analyses suggested that for most areas in the United States, initial colonoscopy would be more cost-effective for the outcomes of detection of adenomas and detection of large adenomas, although very few patients in the study had large adenomas. We conclude that the prevalence of colorectal cancer in persons with colonic symptoms but no evidence of bleeding is low and is comparable with the prevalence in an asymptomatic population. Cost-effective selection of imaging strategies in this population can be based on demographic factors such as age and sex, which are better predictors of the presence of adenomas than are symptoms.

A combined flexible sigmoidoscopy and double-contrast barium enema service: initial experience

BACKGROUND

A service has been instituted offering a combined single-stage procedure of flexible sigmoidoscopy and double-contrast barium enema (FS/DCBE). The results have been reviewed in the first 80 patients to undergo this examination (45 male: 35 female; mean age 61.4 years).

METHODS

Indications for investigation were abdominal pain or suspected diverticular disease (22 patients), altered bowel habit (19), rectal bleeding (17), iron deficiency anemia (6), and miscellaneous (16). FS was followed immediately by DCBE. Radiographs were reviewed by two radiologists unaware of the FS findings.

RESULTS

The extent of FS was to the proximal sigmoid or sigmoid descending colon or splenic flexure in 12.5%, and mid or distal sigmoid in 37.5%. Biopsies were performed at FS in 26 patients (33%). In 67 (84%) of DCBEs the barium coating was assessed as satisfactory or better. FS yielded pathological findings not seen at DCBE in 21 patients (26%). DCBE demonstrated additional abnormalities within the range of the FS examination in 15 patients (19%), almost entirely due to its increased sensitivity for diverticular disease.

CONCLUSION

FS/DCBE is feasible as a one-stage combined procedure. The quality of DCBE following FS is satisfactory, and the extra yield of FS and its potential for biopsy make the combined FS/DCBE a useful technique in the investigation of large bowel disease.

CT of the colon in frail elderly patients

CT is presented as an alternative to barium enema examination for the investigation of the colon in frail elderly patients. Carcinomas can be detected reliably and the investigation is better accepted by patients and staff alike. Furthermore, extracolonic lesions are shown. Obviously small polyps are missed, but such lesions are less relevant in older patients. The CT technique is described, and some of the initial difficulties encountered during the adoption of this policy are discussed.

Contemporary radiological examination of the lower gastrointestinal tract

The morphological spectrum of colonic disease is wide. Various treatment modalities may influence the macroscopic aspect of colonic lesions and render a pathological differential diagnosis occasionally difficult or impossible. Before starting therapy in patients suspected of having colonic disease, a physician should undertake a thorough radiological and endoscopic evaluation of the extent and severity of disease activity in the large bowel (Ruderman and Farmer, 1987). DCBE and colonoscopy are complementary imaging modalities, each test has its own intrinsic advantages and merits (Lichtenstein and Rothstein, 1991). DCBE remains the cornerstone in the detection of fistulas, strictures, perforations and estimating depth of ulcerations. Colonoscopy and biopsy remain the most sensitive imaging modalities to identify mucosal involvement (Dijkstra, 1992). The main clinically relevant discrepancies between colonoscopy and DCBE consist of inflammatory lesions without distortion of the mucosal relief and inflammation in the form of small, superficial erosions and ulcers (Dijkstra, 1992).

Colon cancer detection: an algorithm using endoscopy and barium enema

A review of findings on flexible sigmoidoscopy (FS), colonoscopy and selected double-contrast barium enema (DCBE) radiographs from a group of 66 patients with rectal bleeding was performed to test the value of an algorithm in the detection of colonic cancers and polyps. In this algorithm the FS findings would direct patients either to colonoscopy or to a modified DCBE which focused attention on the colon proximal to the sigmoid. Only patients with neoplasms diagnosed by FS, or by MDCBE after negative FS, would proceed to colonoscopy. The study population contained four cancers, 11 polyps > 5 mm and 11 polyps < or = 5 mm; FS+MDCBE missed four polyps, all < 5 mm. For polyps > 5 mm and cancer, FS+MDCBE had a sensitivity of 100%, a specificity of 82%, a negative predictive value of 1.0 and a positive predictive value of 0.62. Using the algorithm, 24 patients (36%) would have required colonoscopy. The results suggest that FS+MDCBE is a potentially valuable method for screening patients for colonic neoplasia.

Barium enema or computed tomography for the frail elderly patient?

In order to determine whether abdominopelvic computed tomography (CT) offers an alternative to barium enema (BE) for the investigation of the large bowel in frail elderly patients, we have assessed and compared the results of both tests performed in each patient. Thirty-seven patients aged 71 to 88 (mean 80) with a history or clinical findings suggestive of large bowel disease were studied. The seven colonic neoplasms in this group were demonstrated by both techniques (apart from one patient who did not undergo BE as CT had shown an obstructing lesion). CT showed useful additional data in four patients (e.g. abdominal wall involvement) and demonstrated numerous extracolonic lesions (e.g. ovarian carcinoma). However, CT did raise the possibility of a large bowel neoplasm in four patients where none was shown by BE and missed one case of Crohn's disease. CT was the preferred test amongst the 25 patients where the acceptability of the two techniques could be compared. Only in 16 patients were the BE studies adjudged to be of good quality. CT should be the initial investigation of the large bowel in frail elderly patients requiring inpatient bowel preparation; the more unpleasant BE could be reserved for those cases where CT is equivocal or severe symptoms are unexplained.

Barium enema utilization within a defined geographic region: a survey

All 118 hospital-based radiology departments in Indiana (USA) responded to a survey of barium enema (BE) utilization. The percentage of community hospitals in Indiana using barium enema, both single contrast (SCBE) and double contrast (DCBE), for various indications was similar to that reported for major medical centers around the world (RF Thoeni and AR Margulis, Radiology, 167: 7-12, 1988). The use of SCBE and DCBE did not differ between small and large hospitals, or between hospitals in small vs large communities. There was, however, wide variation among community hospitals in their overall use of either contrast technique. Barium enema was usually performed without antecedent sigmoidoscopy. However, 60% of Indiana hospitals perform BE on the same day as flexible sigmoidoscopy. The results indicate that the use of BE in community hospitals in Indiana is similar to that reported for major medical centers. Also like major medical centers, there is no consensus regarding many issues in the performance of BE.

Flexible sigmoidoscopy plus air contrast barium enema versus colonoscopy for suspected lower gastrointestinal bleeding

A randomized, controlled trial was performed to compare the diagnostic yields and cost-effectiveness of two strategies for the evaluation of nonemergent lower gastrointestinal bleeding. Three hundred eighty patients aged greater than or equal to 40 yr were randomized to undergo initial flexible sigmoidoscopy plus air contrast barium enema or colonoscopy; 332 completed the initial studies. Initial colonoscopy detected more cases of polyps less than 9 mm in size, adenomas, and arteriovenous malformations but fewer cases of diverticulosis. No significant difference was found between strategies in the number of patients detected with cancers or polyps greater than or equal to 9 mm in size. In both strategies, cancers were more common in subjects aged greater than or equal to 55 yr (8% overall) than in those aged less than 55 yr (1%). Among patients aged less than 55 yr with suspected lower gastrointestinal bleeding, initial flexible sigmoidoscopy plus air contrast barium enema is a more cost-effective strategy for the detection of colonic neoplasms than initial colonoscopy. However, initial colonoscopy is more cost effective for those aged greater than or equal to 55 yr.

Prospective comparison of double contrast barium enema plus flexible sigmoidoscopy v colonoscopy in rectal bleeding: barium enema v colonoscopy in rectal bleeding

Rectal bleeding often heralds serious colonic disease. The literature suggests that colonoscopy is superior to barium enema plus sigmoidoscopy, although no good comparative studies exist. Seventy one patients with overt rectal bleeding had prospectively flexible sigmoidoscopy, double contrast barium enema and colonoscopy completed independently. Against the gold standard, the sensitivity and specificity of colonoscopy were 0.69 and 0.78 respectively for a spectrum of colonic lesions, while for combined flexible sigmoidoscopy and double contrast barium enema these values were 0.80 and 0.56, respectively. When assessing adenoma or carcinoma, colonoscopy was more sensitive at 0.82 v 0.73, while flexible sigmoidoscopy plus double contrast barium enema was superior for detecting diverticular disease. The positive predictive value for colonoscopy was 0.87 against 0.81 for flexible sigmoidoscopy and double contrast barium enema. This study confirms that colonoscopy should be a first line investigation in subjects likely to require biopsy or therapeutic intervention.

Diagnostic accuracy of double-contrast enema and rectosigmoidoscopy in connection with faecal occult blood testing for the detection of rectosigmoid neoplasms

Four hundred and fifty-eight consecutive subjects with a positive faecal guaiac test when screened for early detection of colorectal neoplasms were investigated with double-contrast enemas and rectosigmoidoscopy (60 cm). The results of these two methods were compared. The radiologists and endoscopists were unaware of the result of each others' examination at the time of their own investigation. Altogether ten subjects with carcinoma in the rectosigmoid area were found. The radiologists and endoscopists each overlooked four of these ten carcinomas and only four of the carcinomas were diagnosed with both methods. Fifty-six of one hundred and seven adenomas were 1 cm or larger in diameter and located in the rectum or the sigmoid colon. Thirteen of the fifty-six adenomas were missed by double contrast enema and ten by endoscopy and only thirty-three adenomas were diagnosed with both methods. Neoplasms in the rectum and the sigmoid colon are sometimes difficult to diagnose with both radiology and endoscopy. Rectosigmoidoscopy (60 cm) should therefore be used as a complement to double contrast enemas if this method is chosen for investigation of a patient with rectal bleeding.