Intelligent Use of the Fecal Immunochemical Test in Population-Based Screening

Analytical evaluation of four faecal immunochemistry tests for haemoglobin

Objectives

Faecal immunochemical tests (FIT) for haemoglobin (Hb) are being used in the investigation of colorectal cancer. These tests use antibodies raised to the globin moiety of human Hb. Here, four automated quantitative FIT systems (HM-JACKarc, NS-Prime, OC-Sensor PLEDIA and SENTiFIT 270) are evaluated analytically to confirm whether the performance of the systems meet the manufacturers' claims.

Methods

Assessment of the analytical performance of the FIT systems was undertaken using Hb lysates, real patient samples and external quality assessment (EQA) samples. This analytical assessment focused on detection characteristics, imprecision, linearity, prozone effect, recovery and carryover.

Results

All four methods demonstrated good analytical performance, with acceptable within- and between-run imprecision, good recovery of f-Hb and limited carryover of samples. They also all show good linearity across the range of concentrations tested. The results of EQA samples showed different variations from the target values (-52 to 45%), due to the absence of standardisation across the different methods.

Conclusions

All four systems are fit for purpose and have an analytical performance as documented by their manufacturers.

Participation in a population-based screening for colorectal cancer using the faecal immunochemical test decreases mortality in 5 years

BACKGROUND

The steady increase in colorectal cancer (CRC) could be reversed through timely secondary prevention (screening) as a main strategy. The aims of this study were to determine the main features of CRC, survival rate and related factors for different types of identified CRCs in a population-based screening programme using the faecal immunochemical test (FIT).

MATERIALS AND METHODS

The CRCs in the susceptible population to be screened between 2009 and 2014 were identified and classified into four groups: (a) nonscreening-detected CRC (diagnosed before first screening invitation and nonparticipants), (b) screening-detected CRC, (c) interval cancer (IC) FIT (diagnosed between screening rounds after a negative FIT) and (d) IC colonoscopy (diagnosed before the colonoscopy surveillance, which is recommended after the screening colonoscopy). Patient demographics and epidemiological characteristics, tumour characteristics and survival were compared between the four groups.

RESULTS

5909 individuals were diagnosed with a CRC. The median follow-up of survival was 4.6 years (range: 0-9 years). The study highlights a significant difference (P<0.0001) in the 5-year survival in the screening-detected CRC group compared with those who had nonscreening-detected CRCs (90.1 vs. 66.7%). Although ICs are not desirable events, the 5-year survival rate is significantly higher with respect to nonparticipants (P<0.0001) (76.3 vs. 60.5%), this being the group with the lowest survival rate.

CONCLUSION

The significantly higher 5-year survival rate of 23.4% of the participants in the screening programme suggests that incidence and mortality rates of CRC will decrease in the near future for participants in screening programmes. A high participation rate is essential to achieve health benefits, irrespective of the type of participation.