Colorectal cancer detection by colonoscopy in a Swedish county, 1979-95

BACKGROUND

Colorectal cancer is the third most common cancer in Sweden, and incidence is increasing. We analysed colorectal cancer detection by colonoscopy in a defined population in Sweden.

METHODS

All colonoscopy records for the period 1979-95 in one Swedish county (population 258,000) were retrieved. Information was obtained about patient demographics, date of examination, endoscopists, indications, findings, colonoscopy type and completion level. Records were linked to the Swedish Cancer Register and the Cause of Death Register.

RESULTS

The majority of 2214 colorectal cancers were detected by means other than colonoscopy. In total, 192 were diagnosed and 6 were not detected by colonoscopy, with no significant differences in gender, age, indications, presence of polyps or diverticulosis, time-period or experience of the endoscopist. The mean completion rate of the endoscopist was lower in patients with undetected cancers. Coexisting inflammatory bowel disease was more common in patients with late diagnosis. Sensitivity was 97.0%, and higher when the indication was bleeding, cancer or unclear X-ray findings.

CONCLUSIONS

Sensitivity in detecting colorectal cancer was high, and the proportion detected by colonoscopy increased over time. Mean completion rate was lower in patients with undetected cancers. Coexisting IBD was more common in patients with a late diagnosis.

The double contrast barium enema: a retrospective single centre audit of the detection of colorectal carcinomas

AIM

To determine retrospectively the sensitivity and specificity of the double contrast barium enema (DCBE) as performed in one institution for the detection of colorectal carcinoma.

SUBJECTS AND METHODS

Eight hundred and eighty barium enema reports were reviewed of consecutive adult patients who underwent DCBE and also had hospital case notes with a minimum follow up of two years, a later diagnostic colonoscopy, or operative and histological findings.

RESULTS

Seventy-four true positive cases of colorectal carcinoma diagnosed at DCBE were confirmed at surgery and histological examination. There were four false positive diagnoses of carcinoma at DCBE. Eight false negative cases at DCBE were demonstrated within a two-year follow-up period. The sensitivity of the DCBE for detecting colorectal carcinoma was therefore 90.2% and the specificity was 99.5%.

CONCLUSION

DCBE is a sensitive and highly specific investigation for the detection of colorectal carcinoma.

Wessex regional radiology audit: barium enema in colo-rectal carcinoma

In the first Wessex regional radiology audit, a retrospective comparison of pathology and radiology reports was made to determine rates of demonstration and reporting of colo-rectal carcinoma on barium enema. Barium enema films were analysed by peer review in cases of discrepancy. The standard set was 100% demonstration and 100% diagnosis of colo-rectal carcinoma on a barium enema undertaken in the 12 months preceding histological diagnosis. The carcinoma demonstration rate was 97% and carcinoma reporting rate 85%. Of 1351 patients with carcinoma, 557 had a barium enema in the preceding 12 months. Four hundred and seventy-one enema reports satisfactorily recorded the malignant lesion (85%). The reasons for non-reporting of a carcinoma were failure to demonstrate the lesion (18 cases, 3%), failure to perceive a demonstrated lesion (23 cases, 4%) and failure to analyse a perceived lesion (45 cases, 8%). Any improvement in demonstration cannot be estimated, but 94% of carcinomas should be reported when improved reporting techniques are instituted and the audit loop is closed.

Radiology in the detection and prevention of colorectal cancer

Imaging techniques available for detection of colorectal cancer include barium enema, endoscopy, computed tomography (CT), ultrasound, magnetic resonance (MR) and immunoscintigraphy. Technical advances continue rapidly and prompt frequent re-evaluation of the optimal approach to management of these patients. Barium enema and colonoscopy are the main techniques for evaluation of symptomatic patients, although CT may well assume the predominant role within a few years. Variation in quality of barium enemas and colonoscopy poses a challenge for continuing medical education (CME) activities. Screening of asymptomatic individuals has to be considered separately for high, moderate and low risk population. Recommendations have to be made at present in the absence of evidence of effectiveness. Staging of disease pre-operatively is of limited value. Follow-up after surgery should be primarily clinical although endoscopy, CT, MR, ultrasound and immunoscintigraphy all have specific roles in the evaluation of patients suspected of harbouring recurrent disease.

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).

Comparison between double-contrast barium enema and colonoscopy to investigate lower gastrointestinal bleeding

A retrospective study was performed to compare the diagnostic accuracy of high-quality double-contrast barium enema (DCBE) against gold standard colonoscopy in 288 patients with suspected lower gastrointestinal bleeding who went through both examinations. Colonoscopy detected the potential cause of bleeding in 99 patients (100%); in order of frequency: polyps greater than or equal to 1 cm (N = 47; 48%), carcinoma (N = 21; 21%), inflammatory bowel disease (IBD) (N = 15; 15%), solitary ulcers (N = 6; 6%), other types of colitis (N = 5; 5%), angiodysplasia (N = 3; 3%), and stenosis (N = 2; 2%). DCBE diagnosed 88 cases (89%) and missed 11 consisting of IBD (N = 4), angiodysplasia (N = 3), solitary ulcers (N = 3), and polyps (N = 1). The overall sensitivity and specificity of DCBE was 0.89 and 0.97, respectively. The sensitivity for carcinoma, polyps, and IBD was 1.00, 0.98, and 0.73, respectively. We conclude that DCBE is very effective to diagnose carcinoma and polyps greater than or equal to 1 cm, the most frequent causes of bleeding, but less effective to diagnose IBD and other nonfrequent causes. If a high-quality DCBE does not reveal the cause of bleeding, the contribution of a following colonoscopy will be to diagnose causes of bleeding other than carcinoma and polyps less than 1 cm and to offer therapeutic possibilities.

Colorectal cancer: the case for barium enema

Both colonoscopy and barium enema are important techniques for examining the colon for polyps and cancer. They are approximately equally sensitive in detecting polypoid lesions of 7 to 10 mm or larger. A major limitation of colonoscopy is that the cecum cannot be visualized in 10 to 36% of cases. The comparable accuracy for detecting significant lesions, greater safety, and greater cost-effectiveness of barium enema favor its use in most patients.

Colonoscopically detected colorectal cancer missed on barium enema

The radiographs and clinical records of 26 patients with colorectal cancer missed on barium enema, and subsequently detected at colonoscopy, were reviewed to determine the cause of radiological error. Twenty (77%) of the patients were female. In 24 of 26 patients, anemia and/or rectal bleeding was a presenting feature. Fourteen of the 26 (54%) missed cancers were in the sigmoid colon, 10 (38%) in the ascending colon or hepatic flexure, and two (8%) in the rectum. Tumor size ranged from 20-100 mm. Fifteen were polyps, and 11 annular cancers. Fourteen (54%) were Dukes C or D tumors. Twenty-eight barium enemas in 23 patients were available for review: 86% were double-contrast studies. In 18 (76%), the cancer could be seen in retrospect and, in over half, the tumor was obvious. The dominant perceptive error was due to missing the lesion in the barium pool. Other major errors were missing the lesion en face or in overlapping loops. As most cancers were missed because of observer perceptive error, by both experienced and inexperienced radiologists, the authors recommend double reporting of all barium enemas.

Case report: persistent colonic spasm concealing a carcinoma--an uncommon diagnostic pitfall of the barium enema examination

Colonic carcinomas may be missed on the barium enema examination for a variety of perceptive, technical, and interpretive reasons. We report an uncommon source of error-persistent bowel spasm resulting in concealment of an underlying carcinoma. Awareness of this association is necessary in the effort to minimize diagnostic pitfalls of the barium enema examination.

Double contrast barium enema and flexible rectosigmoidoscopy: a reliable diagnostic combination for detection of colorectal neoplasm

The efficiency of double contrast barium enema and flexible rectosigmoidoscopy (to 60 cm) in the assessment of patients with a positive Hemoccult II test in a randomized screening study for colorectal neoplasms was evaluated. A positive test was present in 625 patients, of whom 530 had a complete enema and rectosigmoidoscopic assessment. A carcinoma was diagnosed in 26 and an adenoma greater than or equal to 1 cm in diameter in 71. As a control, 323 patients with a negative assessment repeated the Hemoccult II test and of these 67 had a positive second test, of whom 55 underwent colonoscopy. One carcinoma (Dukes' A) and two adenomas greater than or equal to 1 cm in diameter were diagnosed. The efficiency of the assessment was also checked by rescreening the whole group 1-2 years after the first study and by continuing follow-up. It was found that two more carcinomas and one adenoma greater than or equal to 1 cm in diameter had been overlooked at the primary assessment. The sensitivity for neoplasms greater than or equal to 1 cm in diameter at the primary assessment was 72 per cent for double contrast barium enema and 86 per cent for rectosigmoidoscopy. The sensitivity for the combined methods was 94 per cent and the specificity was 99 per cent. The combination of double contrast barium enema and rectosigmoidoscopy in the primary assessment of patients with a positive Hemoccult II test gives an acceptable result and immediate retesting of those with a negative assessment is not necessary.