451. Higher fecal immunochemical test cutoff levels: lower positivity rates but still acceptable detection rates for early-stage colorectal cancers.
- Author
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Terhaar sive Droste JS, Oort FA, van der Hulst RW, van Heukelem HA, Loffeld RJ, van Turenhout ST, Ben Larbi I, Kanis SL, Neerincx M, Räkers M, Coupé VM, Bouman AA, Meijer GA, and Mulder CJ
- Subjects
- Adenoma prevention & control, Adult, Aged, Aged, 80 and over, Cohort Studies, Colonoscopy, Colorectal Neoplasms prevention & control, Early Detection of Cancer, Female, Follow-Up Studies, Humans, Immunoenzyme Techniques, Male, Middle Aged, Neoplasm Staging, Predictive Value of Tests, Sensitivity and Specificity, Survival Rate, Adenoma diagnosis, Colorectal Neoplasms diagnosis, Feces chemistry, Mass Screening
- Abstract
Background: Adjusting the threshold for positivity of quantitative fecal immunochemical tests (FIT) allows for controlling the number of follow-up colonoscopies in a screening program. However, it is unknown to what extent higher cutoff levels affect detection rates of screen-relevant neoplasia. This study aimed to assess the effect of higher cutoff levels of a quantitative FIT on test positivity rate and detection rate of early-stage colorectal cancers (CRC)., Methods: Subjects above 40 years old scheduled for colonoscopy in 5 hospitals were asked to sample a single FIT (OC sensor) before colonoscopy. Screen-relevant neoplasia were defined as advanced adenoma or early-stage cancer (stage I and II). Positivity rate, sensitivity, and specificity were evaluated at increasing cutoff levels of 50 to 200 ng/mL., Results: In 2,145 individuals who underwent total colonoscopy, 79 patients were diagnosed with CRC, 38 of which were with early-stage disease. Advanced adenomas were found in 236 patients. When varying cutoff levels from ≥ 50 to ≥ 200 ng/mL, positivity rates ranged from 16.5% to 10.2%. With increasing cutoff levels, sensitivity for early-stage CRCs and for screen-relevant neoplasia ranged from 84.2% to 78.9% and 47.1% to 37.2%, respectively., Conclusions: Higher FIT cutoff levels substantially decrease test positivity rates with only limited effects on detection rates of early-stage CRCs. However, spectrum bias resulting in higher estimates of sensitivity than would be expected in a screening population may be present., Impact: Higher cutoff levels can reduce strain on colonoscopy capacity with only a modest decrease in sensitivity for curable cancers., (©2010 AACR.)
- Published
- 2011
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