Result card
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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.
10. Zhu MM, Xu XT, Nie F, Tong JL, Xiao SD, Ran ZH. Comparison of immunochemical and guaiac-based fecal occult blood test in screening and surveillance for advanced colorectal neoplasms: A meta-analysis. J Dig Dis 2010; 11(3):148-60.
11. Van Rossum LG, van Rijn AF, Laheij RJ, van Oijen MG, Fockens P, van Krieken HH, et al. Random Comparison of Guaiac and Immunochemical Fecal Occult Blood Tests for Colorectal Cancer in a Screening Population. Gastroenterology 2008; 135(1):82-90.
12. Hol L, Wilschut JA, Van Ballegooijen M, van Vuuren AJ, Van Der Valk H, Reijerink JCIY, et al. Screening for colorectal cancer: Random comparison of guaiac and immunochemical faecal occult blood testing at different cut-off levels. Br J Cancer 2009; 100(7):1103-10.
13. Park DI, Ryu S, Kim YH, Lee SH, Lee CK, Eun CS, et al. Comparison of guaiac-based and quantitative immunochemical fecal occult blood testing in a population at average risk undergoing colorectal cancer screening. Am J Gastroenterol 2010; 105(9):2017-25.
14. Allison JE, Sakoda LC, Levin TR, Tucker JP, Tekawa IS, Cuff T, et al. Screening for colorectal neoplasms with new fecal occult blood tests: update on performance characteristics. J Natl Cancer Inst 2007; 99(19):1462-70.
15. Rabeneck L, Rumble RB, Thompson F, Mills M, Oleschuk C, Whibley A, et al. Fecal immunochemical tests compared with guaiac fecal occult blood tests for population-based colorectal cancer screening. Can J Gastroenterol 2012; 26(3):131-47.