Result card

  • EFF16: How does FIT versus FOBT for CRC screening modify the need for other technologies and use of resources?

How does FIT versus FOBT for CRC screening modify the need for other technologies and use of resources?

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

Internal reviewers: Pseudo125 Pseudo125

Refer to domain search and domain methodology section.

All the systematic reviews and available RCTs included reported statistically significantly higher participation rates for FIT compared with gFOBT {10, 11, 15}. This means a higher charge of diagnostic colonoscopies in the population. With respect to FIT performance, compared with standard gFOBT, current evidence indicates a higher sensitivity for the detection of CRC and advanced adenomas, and higher rates of detection for CRC and advanced adenomas. These advantages of FIT are offset by a higher positivity rate (depending on the used cut-off level), which in turn may require a greater number of colonoscopies. A superior sensitivity and detection rate of adenomas is a distinguishing performance characteristic of FIT compared with gFOBT. These performance characteristics change when the cut-off level in hemoglobin concentration is changed, allowing a screening program to select the optimal cut-off for the program (more cancers and pre-malignant lesions detected with the minimum number of colonoscopies required).

Positive rates varies among randomized clinical trials from FIT 5.5% to gFOBT 3.2% {11}; FIT 4.8% to gFOBT 2.8%{12}; FIT 11.2% to gFOBT 7.9% {13} and FIT 3.2% to gFOBT 10.1%{14}. Differences in positive predictive values for CRC or advanced adenoma were no statistically significant.

The total number of colonoscopies needed to confirm positive test results is higher for FIT comparing to gFOBT. In one RCT{11} 20,623 individuals were invited; 10,301 received gFOBT and 10,322 FIT. Tests were returned by 10,993 individuals, 4836 (46.9%) in the gFOBT group and 6157 (59.6%) in the FIT group. To evaluate the outcome in the 456 positives results, a colonoscopy was performed in 383 (84%) patients. Total number of colonoscopies was 103 in the gFOBT group and 280 in the FIT group. Cancer was found in 11 of the G-FOBTs and in 24 of the FIT. Advanced adenomas were found in 46 of the gFOBT and in 121 of the FIT. The number of polyps found with gFOBT was 220 (of which 154 adenomas) and 679 with FIT (of which 470 adenomas). In this RCT the specificity of the FIT for advanced adenomas and cancer was lower compared with the gFOBT, but the detection rate for advanced adenomas and cancer with the FIT was significantly higher. Consequently, 3 times as many subjects tested with the FIT are referred for a negative colonoscopy. On the other hand, 3 times as many patients with advanced adenomas and 2 times more patients with cancer are left undetected in the gFOBT group compared with the FIT group, ultimately resulting in comparable Positive Predictive Values for both tests. 

González-Enríquez J et al. Result Card EFF16 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: