351. Test immunochimique fécal quantitatif pour l'exploration de patients symptomatiques : une révolution venue des îles britanniques.
- Author
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Denis, Bernard, Guillon, Christelle, L'hirondel, Julien, and Fraser, Callum G.
- Subjects
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MEDICAL screening , *EARLY detection of cancer , *COLORECTAL cancer , *AGE groups , *DETECTION limit - Abstract
Quantitative faecal immunochemical tests (FITs) are no longer reserved for the organised colorectal cancer screening programme. Biogroup laboratories in some area have been replacing qualitative FITs with a quantitative FIT (FOB Gold) for around 1 year, with automated analysis using a multi-purpose routine machine. The sensitivity of qualitative FITs for detecting an advanced neoplasm (CRC or advanced adenoma, i.e. adenoma ≥ 10 mm or high-grade dysplasia or villous or tubulocaval) varies considerably (30% to 73%). In the symptomatic population, sensitivity for CRC is also highly variable, ranging from 82% to 100%, with positivity rates varying from 22% to 35%. These poor results point to the obsolescence of qualitative FITs. In asymptomatic people at average risk of CRC, the sensitivity of the quantitative FIT for diagnosing CRC is 76% at the 10 μg/g threshold and 65% at the 20 μg/g threshold. Lowering the threshold to 20 μg/g would offer better sensitivity, estimated at between 87% and 91% (21% and 25% for advanced adenoma) for a positivity rate of 5.3%, which is perfectly manageable for French gastroenterologists. In symptomatic patients, the performances of the quantitative FITs have sensitivities for the diagnosis of CRC of 91.0% and 94.7% for thresholds set at 10 μg/g and at the limit of detection (2 μg/g). To date, three countries have published recommendations on the use of quantitative FITs for the investigation of symptomatic patients in general practice: the United Kingdom, Spain and Australia, all at a threshold of ≥ 10 μg/g. At the threshold of 2 μg/g, the sensitivity of the quantitative FIT for CRC is evaluated at 94.7% (between 93% and 100% depending on the study), equivalent to that of colonoscopy, and enables colonoscopy to be avoided in 66% of cases. It has been shown that only a minority of people with a family history of CRC are properly screened. It is paradoxical and counter-productive that 50-74-year-olds at high or supposedly high risk of CRC should be subject to the vagaries of opportunistic screening and excluded from the organised screening programme. This is a French exception: most organised screening programmes invite the entire population in the age group concerned to undergo screening, unless they expressly object. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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