Faecal haemoglobin concentration among subjects with negative FIT results is associated with the detection rate of neoplasia at subsequent rounds: a prospective study in the context of population based screening programmes in Italy
Menée en Italie auprès d'une cohorte de 290 038 personnes âgées de 50 à 69 ans et ayant subi entre 2004 et 2010 un premier test FIT dont le résultat s'est avéré négatif, cette étude met en évidence une association entre les concentrations cumulées d'hémoglobine mesurées dans les selles lors des deux premiers tests FIT dont le résultat s'est avéré inférieur au seuil de positivité et le risque de détecter un cancer colorectal de stade avancé lors des sessions de dépistage suivantes
Objective : To estimate the predictive role of faecal haemoglobin (f-Hb) concentration among subjects with faecal immunochemical test (FIT) results below the positivity cut-off for the subsequent risk of advanced neoplasia (AN: colorectal cancer—CRC—or advanced adenoma).
Design Prospective : cohort of subjects aged 50–69 years, undergoing their first FIT between 1 January 2004 and 31 December 2010 in four population-based programmes in Italy.
Methods : All programmes adopted the same analytical procedure (OC Sensor, Eiken Japan), performed every 2 years, on a single sample, with the same positivity cut-off (20 µg Hb/g faeces). We assessed the AN risk at subsequent exams, the cumulative AN detection rate (DR) over the 4-year period following the second FIT and the interval CRC (IC) risk following two negative FITs by cumulative amount of f-Hb concentration over two consecutive negative FITs, using multivariable logistic regression models and the Kaplan-Meier method.
Results : The cumulative probability of a positive FIT result over the subsequent two rounds ranged between 7.8% (95% CI 7.5 to 8.2) for subjects with undetectable f-Hb at the initial two tests (50% of the screenees) and 48.4% (95% CI 44.0 to 53.0) among those (0.7% of the screenees) with a cumulative f-Hb concentration ≥20 µg/g faeces. The corresponding figures for cumulative DR were: 1.4% (95% CI 1.3 to 1.6) and 25.5% (95% CI 21.4 to 30.2) for AN; 0.17% (95% CI 0.12 to 0.23) and 4.5% (95% CI 2.8 to 7.1) for CRC. IC risk was also associated with cumulative f-Hb levels.
Conclusion : The association of cumulative f-Hb concentration with subsequent AN and IC risk may allow to design tailored strategies to optimise the utilisation of endoscopy resources: subjects with cumulative f-Hb concentration ≥20 µg/g faeces over two negative tests could be referred immediately for total colonoscopy (TC), while screening interval might be extended for those with undetectable f-Hb.
Gut , résumé, 2018