RSS Feeds
Accuracy of Screening for Fecal Occult Blood on a Single Stool Sample Obtained by Digital Rectal Examination: A Comparison with Recommended Sampling Practice
- Judith F. Collins, MD;
- David A. Lieberman, MD;
- Theodore E. Durbin, MD;
- David G. Weiss, PhD; and
- and the Veterans Affairs Cooperative Study #380 Group*
- From Department of Veterans Affairs Medical Centers, Portland, Oregon, Long Beach, California, and Perry Point, Maryland.
Abstract
Background: Many expert panels recommend colorectal cancer screening for average-risk asymptomatic individuals older than 50 years of age. Recent studies have found that 24% to 64% of primary care providers use only the digital fecal occult blood test (FOBT) as their primary screening test. The effectiveness of a single digital FOBT is unknown.
Objective: To compare the sensitivity and specificity of digital FOBT and the recommended 6-sample at-home FOBT for advanced neoplasia in asymptomatic persons.
Design: Prospective cohort study.
Setting: 13 Veterans Affairs medical centers.
Patients: 3121 asymptomatic patients 50 to 75 years of age.
Intervention: 2665 patients had 6-sample at-home FOBT and digital FOBT, followed by complete colonoscopy.
Measurements: We measured the sensitivity of digital and 6-sample FOBT for advanced neoplasia and the specificity for no neoplasia. We calculated predictive values and likelihood ratios for advanced neoplasia, defined as tubular adenomas 10 mm or greater, adenomas with villous histology or high-grade dysplasia, or invasive cancer.
Results: Of all participants, 96.8% were men; their average age was 63.1 years. The 6-sample FOBT and the single digital FOBT had specificities of 93.9% and 97.5%, respectively, as defined by studying 1656 patients with no neoplasia. Sensitivities for detection of advanced neoplasia in 284 patients were 23.9% for the 6-sample FOBT and 4.9% for the digital FOBT. The likelihood ratio for advanced neoplasia was 1.68 (95% CI, 0.96 to 2.94) for positive results on digital FOBT and 0.98 (CI, 0.95 to 1.01) for negative results.
Limitations: Most patients were men.
Conclusions: Single digital FOBT is a poor screening method for colorectal neoplasia and cannot be recommended as the only test. When digital FOBT is performed as part of a primary care physical examination, negative results do not decrease the odds of advanced neoplasia. Persons with these results should be offered at-home 6-sample FOBT or another type of screening test.
Article and Author Information
-
*For a list of members of the Veterans Affairs Cooperative Study #380 Group, see the Appendix.
-
Grant Support: By the Cooperative Studies Program, Department of Veterans Affairs, Protocol #380.
-
Potential Financial Conflicts of Interest: None disclosed.
-
Requests for Single Reprints: Judith F. Collins, MD, Portland Veterans Affairs Medical Center, P3-GI, 3710 SW Veterans Hospital Road, PO Box 1034, Portland, OR 97239.
-
Current Author Addresses: Drs. Collins and Lieberman: Portland Veterans Affairs Medical Center, P3-GI, 3710 SW Veterans Hospital Road, PO Box 1034, Portland, OR 97239.
-
Dr. Durbin: West Anaheim Medical Offices, Suite 203, 3010 West Orange Street, Anaheim, CA 92804.
-
Dr. Weiss: Perry Point Veterans Affairs Medical Center, 151E, PO Box 1010, Perry Point, MD 21902.
-
Author Contributions: Conception and design: D.A. Lieberman, D.G. Weiss.
-
Analysis and interpretation of the data: J.F. Collins, D.A. Lieberman, T.E. Durbin, D.G. Weiss.
-
Drafting of the article: J.F. Collins, D.A. Lieberman, T.E. Durbin.
-
Critical revision of the article for important intellectual content: J.F. Collins, D.A. Lieberman, D.G. Weiss.
-
Final approval of the article: J.F. Collins, D.A. Lieberman, T.E. Durbin, D.G. Weiss.
-
Provision of study materials or patients: J.F. Collins, D.A. Lieberman, T.E. Durbin.
-
Statistical expertise: D.A. Lieberman, D.G. Weiss.
-
Obtaining of funding: D.A. Lieberman, D.G. Weiss.
-
Administrative, technical, or logistic support: D.G. Weiss.
-
Collection and assembly of data: J.F. Collins, D.A. Lieberman, T.E. Durbin, D.G. Weiss.
Related Clinical Content
