A population-based comparison of immunochemical fecal occult blood tests for colorectal cancer screening

Background & aims: Quantitative fecal immunochemical tests (FITs) identify individuals with colorectal cancer with greater levels of accuracy than guaiac tests. We compared the performances of 2 FITs in a population undergoing screening for colorectal cancer.

Methods: We collected fecal samples from 19,797 individuals in France (age, 50-74 y) who participated in a colorectal cancer screening program, from June 2009 through May 2011. Samples were analyzed using the Magstream (Fujirebio Inc, Tokyo, Japan) and OC Sensor (Eiken Chemical Co, Tokyo, Japan) (2 samples each) FITs, as well as the Hemoccult II guaiac test (SKD, Villepinte, France) (3 samples each). Colonoscopies were performed for patients with positive results from all 3 tests. The cut-off values for levels of hemoglobin in buffer and stools were 55 ng/mL and 180 μg/g for the Magstream and 150 ng/mL and 30 μg/g for the OC Sensor, respectively. Results from the FITs were compared with those from the guaiac test for cut-off values for stool samples, positivity rates, and the receiver operating characteristic curve values. The numbers needed to screen and the numbers needed to scope to detect an advanced neoplasia (cancer, adenoma ≥10 mm, or high-grade dysplasia) were calculated.

Results: A positive test result was found in 1224 participants (6.2%); 1075 (87.8%) underwent a colonoscopy examination. Of these, 334 were found to have advanced neoplasia. Considering the cut-off values associated with the positivity rate of Hemoccult II (1.6%), the numbers needed to screen were 239 for Hemoccult II, 166 for a 1-sample Magstream FIT, and 129 for a 1-sample OC Sensor FIT; the numbers needed to scope were 3.3, 2.3, and 1.8, respectively. For the same false-positive rate as Hemoccult II (0.98%), the true-positive rates for Magstream and OC Sensor FITs were 0.65% and 0.90% respectively, compared with 0.42% for Hemoccult II. The OC Sensor FIT had a greater area under the receiver operating characteristic curve value than the Magstream FIT.

Conclusions: Based on results from a large, population-based study, the OC Sensor FIT identifies patients with colorectal cancer with greater accuracy than the Magstream FIT. ClinicalTrials.gov number: NCT01251666.