Negative Fecal Occult Blood Test Research Articles

Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests, D.K. Rex, G.A. Lehman, R.H. Hawes, in: Gastroenterology, 100. (1991), 64

Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests, D.K. Rex, G.A. Lehman, R.H. Hawes, in: Gastroenterology, 100. (1991), 64

The Colon Mucus Test in Comparison with the Fecal Occult Blood Test in the Detection of Gastrointestinal Disease

Abstract: This study was undertaken to assess the diagnostic significance of the colon mucus test (CMT) by which the cancer‐associated carbohydrate antigen, β‐D‐Gal (1 ‐ 3)‐D‐GalNAc (T antigen) is measured in rectal mucus, chiefly in patients with various alimentary tract diseases. The incidence of a positive CMT was relatively high in colorectal cancer (69%) and gastric cancer (40%), and was similarly high in some benign colorectal diseases such as colonic diverticulum (42%) and colonic polyps (39%), and in gastric polyps (75%). On the other hand, the incidence of a positive CMT in other benign diseases or in healthy controls was less than 10%. A positive CMT was significantly more common in colorectal disease and in gastric tumors (cancer and polyps) than in the other diseases (p < 0.001). Of 28 colonic polyp patients, 20 (71%) had negative fecal occult blood test results (FOBT), and nine of them (45%) had positive CMT results. These results suggest that the CMT may be a useful screening test for alimentary tract disease, particularly colorectal disease and gastric tumors, although its specificity for colorectal cancer is only moderate. Furthermore, a combination assay using FOBT plus CMT may help to improve the diagnostic rate.

Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests

Colonoscopy was performed on 210 asymptomatic average-risk persons, aged 50–75 years, who had negative fecal occult blood test results. Colonoscopy was complete to the cecum in 209 subjects. Fifty-three subjects (25%) had adenomas and two had cancer. All of the adenomas ≥1 cm in size and both cancers occurred in subjects aged ≥60 years. Fifty-one percent of subjects with adenomas and one with cancer had no neoplasms distal to the sigmoid-descending colon junction. One subject had a major postpolypectomy hemorrhage that stopped spontaneously. Screening colonoscopy, therefore, has a high yield for detection of neoplasms in asymptomatic average-risk persons aged ≥60 years with negative fecal occult blood test results. The yield is low in persons aged 50–54 years and intermediate in persons aged 55–59 years.

Hemoccult Screening and Colorectal Neoplasms

Letters and Corrections1 June 1990Hemoccult Screening and Colorectal NeoplasmsDavid Lieberman, MDDavid Lieberman, MDSearch for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-112-11-880 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptTo the Editor:Allison and associates (1) evaluated the sensitivity of fecal occult blood tests in detecting colorectal neoplasms. The 50% sensitivity they found at 1 year was lower than previous estimates and, as these authors point out, may limit the effectiveness of the fecal occult blood test in colorectal cancer screening programs. The authors also speculate on the likelihood of finding a significant colorectal adenoma in patients with a negative fecal occult blood test. The implication that significant adenomas are unusual (<2%) in patients with a negative fecal occult blood test is unfounded and misleading. Most patients with a...

2. Early Carcinoma and Adenoma of the Large Intestine; Usefulness of Fecal Occult Blood Testing for Detection and Factors Relating to Bleeding

From January 1976 to May 1980, patients presenting overt rectal bleeding or taking fecal occult blood testing included 38 with early colorectal carcinoma treated surgically or endoscopically and 42 with colorectal adenoma excised endoscopically. Of 38 patients with early carcinoma, 22 presented overt rectal bleeding and in 14 the test was positive and in 2 was negative Thus, the overt and or occult bleeding was noted in 95% of 38 patients. Of 42 patients with adenoma, 16 presented overt bleeding, and 20 showed positive and 6 negative respectively. Thus, overt and/or occult bleeding was noted in 86% of patients with adenoma excised endoscopically.The incidence of overt bleeding increased with size in early carcinoma, but was poorly correlated with the size of adenoma.With regard to the location of early carcinoma, overt bleeding was extremely common in rectal tumor and was seen approximately in a half of patients with sigmoid tumor. Adenomas with negative fecal occult blood testing were located mainly proximal to the sigmoid colon. The sigmoid colon has a tendency to bleed easily when rubbed with feces passing through a narrow lumen. Regarding to the shape, overt rectal bleeding was more commonly seen in pedunculated adenoma and sessile early carcinoma. All of 18 carcinomas with submucosal involvement (sm carcinoma) demonstrated either overt or occult bleeding. Only 2 of 20 patients with intramucosal carcinoma (m carcinoma) had negative fecal occult blood testing. Carcinoma without adenomatous component was similar to sm carcinoma regarding to the pattern of bleeding. In contrast, carcinoma in adenoma was similar to adenoma in this respect. In adenoma, no significant correlation was noted between bleeding and severity of histological atypism.

Feasibility of fecal occult-blood testing for detection of colorectal neoplasia.Debits and credits

A screening program for colorectal cancer and adenomas has been applied to 6,579 mostly asymptomatic men and women age 40 years and older utilizing fecal occult-blood testing followed by investigation of patients with positive slides by air-contrast barium enema and colonoscopy. A control population of 7,325 patients had sigmoidoscopy only and no occult-blood testing. Approximately 1% of the patients had positive slides; most patients had only one or two slides positive. Approximately 50% of patients with positive slides had significant neoplastic lesions, including 23 patients with large adenomas and 7 patients with cancers. Pathological staging of cancers was more favorable in the screened asymptomatic group as compared with the control group. Neoplastic lesions seen on sigmoidoscopy in screened patients who had negative fecal occult-blood tests included 2 cancers and 15 large adenomas. Reasons for false negativity include possible conversion of initially positive slides to negative. Screening for colorectal cancer and adenomas with fecal occult-blood testing appears to be feasible approach with good patient compliance, and manageable rate of positive slides productive of a high percentage of neoplastic lesions. The number of false-positives seems to be low. False negativity has been observed and will require further study.