The cumulative risk of false-positive fecal occult blood test after 10 years of colorectal cancer screening
A partir des données portant sur 181 950 tests de recherche de sang occulte dans les selles effectués entre 1997 et 2009 par 94 637 personnes (âge : 50 à 79 ans), cette étude évalue, sur une période de 10 ans, la probabilité d'obtenir un résultat faussement positif chez les personnes effectuant annuellement ce type de test
Background : Annual colorectal cancer screening with fecal occult blood test (FOBT) is a non-invasive alternative to screening colonoscopy once every ten years. If false-positive FOBT results are common, then many patients selecting an FOBT regimen will be exposed to the same invasive testing as those selecting a colonoscopy regimen. The objective of this study was to estimate the probability of experiencing a false-positive after receiving annual FOBT screening for 10 years.
Methods : Medical records for patients age 50-79 years receiving FOBT screening with Hemoccult Sensa between 1997 and 2009 at Group Health of Washington State captured the date and results of each FOBT, along with subsequent colorectal cancer diagnoses. We used logistic regression to analyze associations between patient characteristics and odds of a positive FOBT with no invasive cancer diagnosis within one year (FOBT+, CRC-). We estimated the probability of receiving at least one FOBT+, CRC- result after 10 years of screening.
Results : We observed 181,950 FOBTs from 94,637 individuals. Older patients, males, and non-white patients were significantly more likely to receive FOBT+, CRC- results (p < 0.001 for all risk factors). After 10 years of annual FOBT, 23.0% (95% confidence interval [18.2, 27.0]) will receive at least one FOBT+, CRC- result.
Conclusions : Most patients participating in annual FOBT screening over 10 years will not have a positive result, reinforcing the potential value of this regimen as a non-invasive alternative to colonoscopy.
Impact : Annual stool-based screening is a screening alternative resulting in substantially fewer colonoscopies than once per decade colonoscopy.
Cancer Epidemiology Biomarkers & Prevention , résumé, 2013