Evaluation of an immunochemical fecal occult blood test with automated reading in screening for colorectal cancer in a general average‐risk population

Abstract

Colorectal cancer screening is a high public health priority in all industrialized countries. However, the low sensitivity of the common guaiac screening test (HemoccultII) makes practitioners and public health decision makers reluctant to set up a national screening program. In recent years, immunochemical tests based on the use of a specific antibody have been found to be more sensitive than the HemoccultII test. However, for screening purposes, any gain in sensitivity is of interest only if specificity and positive predictive value are satisfactory. Our aim was to assess the performance of an immunochemical test with an automated reading technique (Magstream 1000) for different hemoglobin content cut‐off points. The study was carried out in the general population aged 50–74 years in the geographic area of Cotentin (Normandy, France). From 1 January 2001 to 31 December 2002, 7,421 one‐time screening tests (Magstream) were administered by general practitioners and occupational physicians to patients at the end of regular consultations. Colonoscopy was proposed to the 434 people with a positive test. All cancers occurring in the study population between 1 January 2001 and 31 December 2003 were collected by general practitioners, gastroenterologists and the local registry. At the usual positivity threshold (20 ng hemoglobin/ml), screening sensitivity and specificity at 2 years of follow‐up with 95% CIs were, respectively, 0.85 (0.72–0.98) and 0.94 (0.94–0.95). If the hemoglobin content cut‐off point had been set at 50 ng/ml instead of the usual cut‐off, positivity would have been 3.1% and positive predictive value for a cancer or a large adenoma would have been 0.49, with sensitivity of 0.68–0.83 and specificity of 0.97. Our results suggest that use of an immunochemical test with an automated reading technique could improve the prospects for mass‐screening for colorectal cancer since it offers a promising alternative to guaiac tests. © 2005 Wiley‐Liss, Inc.

Comparison of a guaiac and an immunochemical faecal occult blood test for the detection of colonic lesions according to lesion type and location

“…Our previous studies have demonstrated that I-FOBT is preferable to G-FOBT from a public health point of view because the availability of quantitative Hb measurement offers the possibility to choose a positivity rate offering both high sensitivity and high specificity (Launoy et al, 2005;Guittet et al, 2007). This study suggests that I-FOBT is also preferable to G-FOBT from a clinical point of view, because it is capable of detecting good prognosis cancers of the rectum and high-risk adenomas that are missed by G-FOBT.…”

Sensitivity of latex agglutination faecal occult blood test in the Florence District population-based colorectal cancer screening programme

“…Zappa et al (2001) used the proportional interval cancer incidence method, and reported 1-and 2-year sensitivity estimates for CRC for 1-day RPHA testing of 89 and 82%, respectively, whereas corresponding estimates for 3-day G-FOBT were 64 and 50%, respectively. Using the traditional method, Launoy et al (2005) reported a 2-year sensitivity estimate of 85% for a RPHA-derived test (Magstream) with a low-positivity cutoff and a recall rate of 6%.…”

Sensitivity and Specificity of Community Fecal Immunotesting Screening for Colorectal Carcinoma in a High-Risk Canadian Population

“…6,8 Reported sensitivities in these studies have ranged from 40.5% to 94%. 7,8,21 Our results are likely more reflective of the expectations for a community-based program. We report AUCs for colorectal carcinoma in subgroup analysis of 0.75 to 0.85, which are considerably lower than those reported by Tao et al, 22 who reported AUCs for the 3 quantitative tests of 0.90 to 0.92.…”

“…5 Recent research, however, has indicated that FIT is more sensitive than fecal occult blood tests as well as being more convenient for patients. [6][7][8][9][10] Fecal immunochemical testing also offers advantages to clinical laboratories, including the potential for automation, the ability to customize the cutoff level to define a positive test, and improved cost-effectiveness. [11][12][13][14][15][16] Finally, by eliminating patients who do not need a colonoscopy, a FIT screening program may be more cost-effective than colonoscopybased screening.…”