Higher fecal immunochemical test cutoff levels: lower positivity rates but still acceptable detection rates for early-stage colorectal cancers.
Cancer Epidemiol Biomarkers Prev
; 20(2): 272-80, 2011 Feb.
Article
in En
| MEDLINE
| ID: mdl-21135261
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Colorectal Neoplasms
/
Adenoma
/
Mass Screening
/
Feces
Type of study:
Diagnostic_studies
/
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
/
Screening_studies
Limits:
Adult
/
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Cancer Epidemiol Biomarkers Prev
Journal subject:
BIOQUIMICA
/
EPIDEMIOLOGIA
/
NEOPLASIAS
Year:
2011
Type:
Article
Affiliation country:
Netherlands