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.

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.

High rate of advanced adenoma detection in 4 rounds of colorectal cancer screening with the fecal immunochemical test.

BACKGROUND & AIMS: Few data have been published on the performance of colorectal cancer (CRC) screens that use multiple rounds of the fecal immunochemical test (FIT). We evaluated outcomes of 4 screening rounds in over 7 years in an Italian population-based program. METHODS: We conducted a prospective cohort study of 2959 average-risk subjects, aged 50-74 years, who were invited for the first screening round in 2001. We assessed the participation rate, the yield of advanced adenomas and CRC detected in the screening examinations, and we collected information about interval CRCs, with a follow-up period of 8.5 years. RESULTS: Participation in each round varied from 56% to 63%; 48.1% of eligible subjects attended all 4 invitations. The positive predictive value of the FIT for advanced neoplasia (CRC or advanced adenoma) was 40% at the first round, and approximately 33% in the subsequent rounds. This decrease was attributable mainly to a decrease in the detection of CRC, although a high rate of advanced adenomas (range, 0.8%-1.7%) was observed over all rounds. To find one advanced neoplasia in the study period the number of people that needed to be screened was 28, and the number of tests needed was 74. CONCLUSIONS: About 60% of invited individuals participated in every single round of FIT screening for CRC, but less than 50% attended all 4 tests. A high detection rate of advanced adenomas in all rounds indicates that FIT screening could have a higher impact on incidence of CRC than the guaiac fecal occult blood test.