IFOBTs moderately sensitive and highly specific for colon cancer

Clinical Question

Are immunochemical fecal occult blood tests sensitive and specific enough to be used for colorectal cancer screening?

Bottom Line
Immunochemical fecal occult blood tests (IFOBTs), such as OC-Micro, OC-Sensor, or OC-Light, are moderately sensitive (73% – 89%) and highly specific (92% – 95%) for identifying colorectal cancer. In comparison, Homoccult Sensa has a lower sensitivity (64% – 80%) and specificity (87% – 90%). IFOBTs also have the advantage of requiring only one sample. (LOE = 1c)

Reference

Lee JK, Liles EG, Bent S, Levin TR, Corley DA. Accuracy of fecal immunochemical tests for colorectal cancer: systematic review and meta-analysis. Ann Intern Med 2014;160(3):171-181.

Study Design: Meta-analysis (other) Funding: Government
Setting: Various (meta-analysis) Allocation: Unknown

Synopsis

These researchers searched 5 databases and the reference lists of included studies, finding 19 eligible studies that evaluated the diagnostic accuracy of IFOBTs. Two authors used the STARD and PRISMA protocols and independently determined study eligibility, extracted the data, and evaluated study quality. They included cohort studies and randomized studies that used colonoscopy or longitudinal follow-up as the gold standard and only included studies published in English. They excluded studies or results that evaluated only the detection of adenomas. Limiting analysis to only currently available IFOBTs found a sensitivity of 82% (95% CI, 73% – 89%) and a specificity of 94% (92% – 95%). These numbers translate into a positive likelihood ratio of 13.10 and a negative likelihood ratio of 0.19. There was no difference in performance among different commercial products, and multiple sampling was no more accurate than a single sample. Heterogeneity among the studies was acceptable when removing products that are not commercially available. There was some evidence of publication bias. There are no head-to-head studies comparing one type of test with another, and no research evaluating the effectiveness of IFOBT testing on cancer-related mortality or all-cause mortality.

Allen F. Shaughnessy, PharmD, MMedEd
Professor of Family Medicine
Tufts University
Boston, MA

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