MR-Kolonografie bei stationären Patienten: Durchführbarkeit und Sensitivität

Developments in Screening Tests and Strategies for Colorectal Cancer

BACKGROUND

Worldwide, colorectal cancer (CRC) is the third most common cancer in men and second most common in women. It is the fourth most common cause of cancer mortality. In the United States, CRC is the third most common cause of cancer and second most common cause of cancer mortality. Incidence and mortality rates have steadily fallen, primarily due to widespread screening.

METHODS

We conducted keyword searches on PubMed in four categories of CRC screening: stool, endoscopic, radiologic, and serum, as well as news searches in Medscape and Google News.

RESULTS

Colonoscopy is the gold standard for CRC screening and the most common method in the United States. Technological improvements continue to be made, including the promising "third-eye retroscope." Fecal occult blood remains widely used, particularly outside the United States. The first at-home screen, a fecal DNA screen, has also recently been approved. Radiological methods are effective but seldom used due to cost and other factors. Serum tests are largely experimental, although at least one is moving closer to market.

CONCLUSIONS

Colonoscopy is likely to remain the most popular screening modality for the immediate future, although its shortcomings will continue to spur innovation in a variety of modalities.

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.

Ureterosigmoidostomy associated signet ring colon cancer presenting as hip pain

PURPOSE

We present a case of a young male with a history of ureterosigmoidostomy who presented with hip pain, the subsequent workup of which revealed metastatic bone lesions from a primary sigmoid signet ring cell adenocarcinoma.

METHODS

Review of literature was conducted using databases PubMed Medline (1966-current), PubMed Central (1970-current), and EMBASE (1988-2009) to explore previous studies on the topic; used the Surveillance, Epidemiology and End Results Program for epidemiological data; and used the National Comprehensive Cancer Network guidelines for management recommendations.

RESULTS

Ureterosigmoidostomy is well-documented risk factor for colonic neoplasms, the reported incidence being 2-41% with a latent period of 10 to 30 years and a risk of occurrence 80-7,000 times higher than in the general population. The most common histological type of colon cancer seen after ureterosigmoidostomy is adenocarcinoma, but cases of signet-ring cell carcinoma have also been described. Signet-ring cell adenocarcinoma occurs predominantly in stomach but may infrequently arise from other organs such as breast, urinary bladder, and small and large bowel.

CONCLUSIONS

This case underscores the importance of prolonged screening in patients with ureterosigmoidostomies and also calls for heightened awareness among primary care physicians regarding long-term risks associated with this unique entity.

Magnetic resonance (MR) colonography in the detection of colorectal lesions: a systematic review of prospective studies

Objective

To determine the diagnostic accuracy of MR-colonography for the detection of colorectal lesions.

Methods

A comprehensive literature search was performed for comparative MR-colonography studies, published between May 1997 and February 2009, using the MEDLINE, EMBASE and Cochrane databases. We included studies if MR-colonography findings were prospectively compared with conventional colonoscopy in (a)symptomatic patients. Two reviewers independently extracted study design characteristics and data for summarising sensitivity and specificity. Heterogeneity in findings between studies was tested using I² test statistics. Sensitivity and specificity estimates with 95% confidence intervals (CI) were calculated on per patient basis and summary sensitivity on per polyp basis, using bivariate and univariate statistical models.

Results

Thirty-seven studies were found to be potentially relevant and 13 fulfilled the inclusion criteria. The study population comprised 1,285 patients with a mean disease prevalence of 44% (range 22–63%). Sensitivity for the detection of CRC was 100%. Significant heterogeneity was found for overall per patient sensitivity and specificity. For polyps with a size of 10 mm or larger, per patient sensitivity and specificity estimates were 88% (95% CI 63–97%; I² = 37%) and 99% (95% CI 95–100%; I² = 60%). On a per polyp basis, polyps of 10 mm or larger were detected with a sensitivity of 84% (95% CI 66–94%; I² = 51%). The data were too heterogeneous for polyps smaller than 6 mm and 6–9 mm.

Conclusion

MR-colonography can accurately detect colorectal polyps more than 10 mm in size