Result card

  • EFF22: How does FIT compare to gFOBT for CRC screening in terms of accuracy measures?
English

How does FIT compare to gFOBT for CRC screening in terms of accuracy measures?

Authors: Jesús González-Enríquez, Francesca Gillespie, Stefania Lopatriello, Iñaki Imaz

Internal reviewers: Pseudo125 Pseudo125

Please refer to EFF 20

We identified 5 systematic reviews {10,15,16,17,18} and 3 additional diagnostic cohort trials {19,20,21} directly comparing FIT vs gFOBT and they are listed in table 9 with R-AMSTAR and risk of bias results. Data reported on accuracy measures are presented in the relative column of above mentioned table, starting from the more robust available evidence.

Overall 6 out of the 8 studies in the table conclude that FIT is more accurate and preferable to gFOBT for CRC screening.

The most recent and high quality review {15} analyses the performance characteristics of FIT compared with gFOBT, including two randomized control trials {11,12} and two observational studies{13,14}. In summary, the sensitivity of FIT for detecting CRC and AA compared with a standard gFOBT is superior. In the two randomized control trials, specificity was decreased for CRC and Advanced Adenoma when using FIT compared with gFOBT. On the other hand, these two studies reported higher advanced neoplasia detection rates for FIT compared with gFOBT. The PPV for detecting CRC and Advanced Adenoma using FIT is not different from the standard gFOBT. In general, the positivity rates for FIT using the manufacturer’s standard cut-off level in hemoglobin concentration are higher than for gBOBT. Please refer to Table 9 for values of accuracy measures.

 

Overall, FIT performance is superior to the standard gFOBT for the detection of CRC and adenomas. FIT has additional important advantages compared to gFOBT: higher screening participation rates, potential for automation in the laboratory and to select the cut-off level of hemoglobin concentration that defines a positive test. However, the following potential disadvantages are: greater specimen instability and possibly higher positivity rates.

No merging of available data has been performed do to the wide variability in settings and presented outcomes.

Need for further research:

  • More well-designed randomized controlled studies directly comparing guaiac and FIT.
  • The use the Standards for Reporting of Diagnostic Accuracy guidelines is recommended for reporting future diagnostic accuracy studies.
  • Studies should ideally recruit a representative screening population, use colonoscopy to confirm diagnosis regardless of the FOBT result, measure the detection of CRC and adenomas and report the results separately and combined, and allow outcome assessors access to clinical information that would be available in practice, but blind them to other information.
  • Specimen instability issue must be considered in each setting.
  • The type of FIT and associated costs, the appropriate haemoglobin cut-off to use, and the capacity for follow-up by colonoscopy or flexible sigmoidoscopy may contribute to deciding if FIT is an appropriate CRC screening tool.

 

Critical
Partially
González-Enríquez J et al. Result Card EFF22 In: González-Enríquez J et al. Clinical Effectiveness In: Jefferson T, Cerbo M, Vicari N [eds.]. Fecal Immunochemical Test (FIT ) versus guaiac-based fecal occult blood test (FOBT) for colorectal cancer screening [Core HTA], Agenas - Agenzia nazionale per i servizi sanitari regionali; 2014. [cited 16 June 2021]. Available from: http://corehta.info/ViewCover.aspx?id=206

References