Gastroenterology

Gastroenterology

Volume 135, Issue 1, July 2008, Pages 82-90
Gastroenterology

Clinical–Alimentary Tract
Random Comparison of Guaiac and Immunochemical Fecal Occult Blood Tests for Colorectal Cancer in a Screening Population

https://doi.org/10.1053/j.gastro.2008.03.040Get rights and content

Background & Aims: Despite poor performance, guaiac-based fecal occult blood tests (G-FOBT) are most frequently implemented for colorectal cancer screening. Immunochemical fecal occult blood tests (I-FOBT) are claimed to perform better, without randomized comparison in screening populations. Our aim was to randomly compare G-FOBT with I-FOBT in a screening population. Methods: We conducted a population-based study on a random sample of 20,623 individuals 50–75 years of age, randomized to either G-FOBT (Hemoccult-II) or I-FOBT (OC-Sensor). Tests and invitations were sent together. For I-FOBT, the standard cutoff of 100 ng/ml was used. Positive FOBTs were verified with colonoscopy. Advanced adenomas were defined as ≥10 mm, high-grade dysplasia, or ≥20% villous component. Results: There were 10,993 tests returned: 4836 (46.9%) G-FOBTs and 6157 (59.6%) I-FOBTs. The participation rate difference was 12.7% (P < .01). Of G-FOBTs, 117 (2.4%) were positive versus 339 (5.5%) of I-FOBTs. The positivity rate difference was 3.1% (P < .01). Cancer and advanced adenomas were found, respectively, in 11 and 48 of G-FOBTs and in 24 and 121 of I-FOBTs. Differences in positive predictive value for cancer and advanced adenomas and cancer were, respectively, 2.1% (P = .4) and −3.6% (P = .5). Differences in specificities favor G-FOBT and were, respectively, 2.3% (P < .01) and −1.3% (P < .01). Differences in intention-to-screen detection rates favor I-FOBT and were, respectively, 0.1% (P < .05) and 0.9% (P < .01). Conclusions: The number-to-scope to find 1 cancer was comparable between the tests. However, participation and detection rates for advanced adenomas and cancer were significantly higher for I-FOBT. G-FOBT significantly underestimates the prevalence of advanced adenomas and cancer in the screening population compared with I-FOBT.

Section snippets

Population

The population in this prospective study was a random selection of the general Dutch population between 50 and 75 years of age in Nijmegen, Amsterdam, and surrounding areas. Population data with respect to date of birth, gender, and postal area were provided by the civil service of the municipalities and updated every 8 weeks to keep the database up to date with respect to moving, age, and death. Institutionalized and symptomatic people were excluded. Symptomatic people were advised to contact

Population

Overall 20,623 individuals were invited; 10,301 received a G-FOBT and 10,322 an I-FOBT (Figure 1). The mean age of the invited individuals was 60.7 ± 7.1 years (mean ± SD) and was not different between the FOBT groups. More women than men were randomly selected with a difference of 3.4% (95% CI, 2.5–4.4; P < .01). After test allocation, gender differences were equal for both tests (Table 1).

Tests were returned by 10,993 individuals, 4836 (46.9%) in the G-FOBT group and 6157 (59.6%) in the

Discussion

In this population study, we randomly compared the performance of a G-FOBT with an I-FOBT in a previously screening naïve population.33 Another study comparing G-FOBT (Hemoccult-II) with I-FOBT was not randomized, included far fewer persons, and used a different I-FOBT. This I-FOBT(!nform) was not quantitative, making quality control less adequate.10 Despite these drawbacks, the results of this study were in line with ours. Other studies evaluating I-FOBTs included far less subjects and did not

References (46)

  • N. Segnan et al.

    Comparing attendance and detection rate of colonoscopy with sigmoidoscopy and FIT for colorectal cancer screening

    Gastroenterology

    (2007)
  • M. Betes et al.

    Use of colonoscopy as a primary screening test for colorectal cancer in average risk people

    Am J Gastroenterol

    (2003)
  • J.R. Stroehlein et al.

    Hemoccult detection of fecal occult blood quantitated by radioassay

    Am J Dig Dis

    (1976)
  • S.J. Winawer

    Fecal occult blood testing

    Am J Dig Dis

    (1976)
  • K.M. Cummings et al.

    Screening for colorectal cancer using the Hemoccult II stool guaiac slide test

    Cancer

    (1984)
  • J.D. Hardcastle et al.

    Fecal occult blood screening for colorectal cancer in the general populationResults of a controlled trial

    Cancer

    (1986)
  • J. Faivre et al.

    Participation in mass screening for colorectal cancer: results of screening and rescreening from the Burgundy study

    Eur J Cancer Prev

    (1991)
  • S.F. Miller et al.

    The early detection of colorectal cancer

    Cancer

    (1977)
  • J.S. Mandel et al.

    The effect of fecal occult-blood screening on the incidence of colorectal cancer

    N Engl J Med

    (2000)
  • G.D. Launoy et al.

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

    Int J Cancer

    (2005)
  • A. Vilkin et al.

    Performance characteristics and evaluation of an automated-developed and quantitative, immunochemical, fecal occult blood screening test

    Am J Gastroenterol

    (2005)
  • Z. Levi et al.

    A quantitative immunochemical fecal occult blood test for colorectal neoplasia

    Ann Intern Med

    (2007)
  • N. Gopalswamy et al.

    A comparative study of eight fecal occult blood tests and HemoQuant in patients in whom colonoscopy is indicated

    Arch Fam Med

    (1994)
  • Cited by (643)

    View all citing articles on Scopus

    Supported by the Netherlands Organization for Health Research and Development (ZonMW: number 50-50115-98-060, project 63000004). This organization had no influence on any aspect relevant to this study.

    This trial is registered under ISRCTN57917442 at Current Controlled Trials (www.controlled-trials.com).

    View full text