主页 > 医学动态 >
【medical-news】直肠癌筛查: 直肠镜 PK CT检查
Colon Cancer Screening: Colonoscopy versus CT Scanning
Posted by Jacob Goldstein
CT scans can detect about 90% of the medium and large lesions and cancers detected by colonoscopy, a study in this week’s New England Journal of Medicine found.
The finding suggests that people who can’t stand the idea of a colonoscopy could opt for a CT scan instead (sometimes known as virtual colonoscopy), rather than skip a screening test altogether. But those who get CT tests, like those who get colonoscopies, still have to take strong laxatives. Then, if the CT scans shows a lesion, you still have to have a follow-up colonoscopy.
What’s more, CT scans showed possible problems outside the colon that needed to be followed up in 16% of the 2,600 patients in the study. That’s pretty often, especially given that the follow-ups can often require lots of stressful testing but turn out to be nothing in the vast majority of cases.
And even those that do turn out to be a real problem often can’t be treated effectively, an editorial published along with the study noted. (On the other hand, there may be cases where catching something outside the colon could save a patient’s life.)
Despite all the attention given to colonoscopy and CT scans, a third kind of test, called fecal occult blood testing (FOBT) is the only screening technique that has been clearly shown to reduce death from colon cancer, said H. Gilbert Welch, a Dartmouth doc who studies cancer screening and practices at the VA. And overall, there’s not enough evidence to say whether CT scans, colonoscopy or FOBT is the best.
“It’s a close call among all three of these,” said Welch, whose father died of colon cancer and who had a colonoscopy when he turned 50. “I would tend to stay away from CT colonography because it has this additional problem that you see all sorts of other things.”
Still, given that lots of people don’t get any screening at all, CT scans may be better than nothing Accuracy of CT Colonography for Detection of Large Adenomas and Cancers
http://content.nejm.org/cgi/content/short/359/12/1207
ABSTRACT
Background Computed tomographic (CT) colonography is a noninvasive option in screening for colorectal cancer. However, its accuracy as a screening tool in asymptomatic adults has not been well defined.
Methods We recruited 2600 asymptomatic study participants, 50 years of age or older, at 15 study centers. CT colonographic images were acquired with the use of standard bowel preparation, stool and fluid tagging, mechanical insufflation, and multidetector-row CT scanners (with 16 or more rows). Radiologists trained in CT colonography reported all lesions measuring 5 mm or more in diameter. Optical colonoscopy and histologic review were performed according to established clinical protocols at each center and served as the reference standard. The primary end point was detection by CT colonography of histologically confirmed large adenomas and adenocarcinomas (10 mm in diameter or larger) that had been detected by colonoscopy; detection of smaller colorectal lesions (6 to 9 mm in diameter) was also evaluated.
Results Complete data were available for 2531 participants (97%). For large adenomas and cancers, the mean (±SE) per-patient estimates of the sensitivity, specificity, positive and negative predictive values, and area under the receiver-operating-characteristic curve for CT colonography were 0.90±0.03, 0.86±0.02, 0.23±0.02, 0.99±<0.01, and 0.89±0.02, respectively. The sensitivity of 0.90 (i.e., 90%) indicates that CT colonography failed to detect a lesion measuring 10 mm or more in diameter in 10% of patients. The per-polyp sensitivity for large adenomas or cancers was 0.84±0.04. The per-patient sensitivity for detecting adenomas that were 6 mm or more in diameter was 0.78.
Conclusions In this study of asymptomatic adults, CT colonographic screening identified 90% of subjects with adenomas or cancers measuring 10 mm or more in diameter. These findings augment published data on the role of CT colonography in screening patients with an average risk of colorectal cancer. (ClinicalTrials.gov number, NCT00084929 [ClinicalTrials.gov] ; American College of Radiology Imaging Network [ACRIN] number, 6664.)
Source Information
From Mayo Clinic Arizona, Scottsdale, AZ (C.D.J., A.K.H.); Brown University Center for Statistical Sciences, Providence, RI (M.-H.C., B.A.H.); Biostatistics Consulting, Toronto (A.Y.T.); Mallinckrodt Institute of Radiology, Washington University, St. Louis (J.P.H., C.O.M.); University of Chicago, Chicago (A.D.); Scottsdale Medical Imaging, Scottsdale, AZ (M.D.K.); Beth Israel Deaconess Medical Center, Boston (B.S.); Yale University, New Haven, CT (J.I.C.); Radiology Imaging Associates, Denver (R.G.O.); Mayo Clinic Rochester, Rochester, MN (J.L.F., P.J.L.); University of California, Los Angeles, Los Angeles (P.Z.); Johns Hopkins University, Baltimore (K.M.H.); Memorial Medical Center, Springfield, IL (K.C.); University of Texas M.D. Anderson Cancer Center, Houston (R.B.I.); Virginia Commonwealth University, Richmond (R.A.H.); University of California, San Diego, San Diego (G.C.); University of California and San Francisco Veterans Affairs Medical Center, San Francisco (J.Y.); and Abbott Northwestern Hospital, Minneapolis (L.J.B
阅读本文的人还阅读：
作者:admin@医学,生命科学 2011-04-18 10:18
医学,生命科学网