Study of In-home Tests for Colorectal Cancer
Condition: Colorectal Cancer
MeSH terms: Colorectal Neoplasms
Study type: Interventional

Summary: 
      The objective of this study is to compare the performance characteristics or accuracy of
      different in-home screening tests for colorectal cancer (fecal occult blood tests), among
      patients without symptoms of colorectal cancer. Patients who meet study eligibility criteria
      and agree to participate in the study are asked to perform one guaiac and two immunochemical
      fecal occult blood tests at home prior to their colonoscopy. After the patient has completed
      and sent in the test kits, the patient then undergoes their previously scheduled colonoscopy.
      Accuracy and performance characteristics for each type of fecal occult blood test, including
      sensitivity, specificity, test positivity rate and positive predictive value for advanced
      colorectal neoplasia (advanced colorectal polyps) or colorectal cancer, will be estimated by
      comparing the fecal occult blood test results with the results of the colonoscopy.
    

Detailed description: 
      One of the recommended options for colorectal cancer screening in the population at average
      risk for colorectal cancer is annual fecal occult blood test (FOBT) starting at age 50.
      Randomized controlled trials have shown that annual or biennial fecal occult blood testing
      using a guaiac-based test reduces incidence and mortality from colorectal cancer. However,
      the sensitivity and specificity of the guaiac-based tests is relatively low. Guaiac-based
      fecal tests can produce false-positive or false-negative results with certain foods,
      vitamins, or medications, so dietary restrictions are generally recommended before the test.
      Newer, immunochemical FOBTs use antibodies to detect the globin portion of human hemoglobin
      and do not require dietary restrictions. These immunochemical tests may have improved
      performance characteristics (sensitivity and specificity) compared with the guaiac-based
      tests. However, there have been few studies of the performance characteristics of the
      immunochemical tests in the average-risk population, particularly for the iFOBTs that are
      currently available in the U.S. There are several iFOBT tests on the U.S. market which may
      have different performance characteristics.

      Some of the newer immunochemical tests also have the advantage of having a simpler sampling
      procedure for the patient. Guaiac-based FOBTs generally use sticks or spatulas to collect
      specimens from three stools that have not contacted toilet bowl water; these specimens are
      then smeared on test cards. However, some immunochemical tests allow sample collection by
      brushing the surface of the stool while it is in the toilet bowl water. In addition, some
      immunochemical tests only require samples from one or two stools.

      Colorectal cancer is a leading cause of cancer-related morbidity and mortality. Key policy
      groups including the ACS, the American College of Radiology, the U.S. Multi-society Task
      Force on Colorectal Cancer, and the U.S. Preventive Services Task Force recommend the FOBT
      (guaiac or immunochemical-based) as one of several appropriate screening strategies for
      colorectal cancer. Although colonoscopy has higher sensitivity and specificity than FOBT in
      detecting advanced colorectal neoplasia, colonoscopy is an invasive test that has several
      potential disadvantages when screening the average-risk population, including higher costs,
      capacity limitations, and increased risk of complications. Immunochemical FOBT may have some
      advantages over both guaiac-based FOBT and colonoscopy for screening the average-risk
      population, including better performance characteristics and better patient acceptability
      than gFOBT and lower costs than colonoscopy. Unfortunately, the scientific literature on the
      sensitivity and specificity of the respective tests is not sufficient to support more
      specific recommendations about which test is best for routine screening among asymptomatic
      adults. This study will address that crucial gap in the literature.
    

Intervention name(s): fecal occult blood tests
Intervention type(s): Other
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Screening
Keywords: colorectal cancer; mass screening; fecal occult blood