Comparative Study of Colon Capsule and Virtual Colonoscopy (VICOCA)
Condition: Colonic Polyps; Adenoma
MeSH terms: Adenoma; Colonic Polyps
Study type: Observational [Patient Registry]

Summary: 
      Summary Colorectal cancer (CRC) represents the second leading cause of cancer deaths in Spain
      (11,000 deaths per year). Screening of the population over 50 years of age with no
      significant history (intermediate risk) is recommended, but which screening method is best
      for promoting adherence in this type of patient has not been well established. There are
      currently two screening methods that are less invasive than conventional colonoscopy and seem
      to have higher sensitivity than the test for faecal occult blood (FOBT). These two methods
      are the colon capsule, which consists in ingesting a capsule that takes photographs of the
      colon, and virtual colonoscopy, which is a radiological technique.

      Objectives: 1. To demonstrate that virtual colonoscopy and colon capsule are effective CRC
      screening techniques in the intermediate risk population, with diagnostic rates comparable to
      conventional colonoscopy (concordance). 2. To compare the diagnostic rates of the colon
      capsule and virtual colonoscopy with respect to the size and characteristics of the lesions
      visualised. 3. To compare the participation rates for each screening strategy and identify
      the factors that influence participation (individual, family, and socioeconomic factors as
      well as those relating to the doctor).
    

Detailed description: 
      Based on the fact that CRC is an important healthcare issue and that there is enough evidence
      to show that this disease, if diagnosed early, is curable and at a reasonable cost, the
      European Community Council, in 2003, issued directives that member states would make
      population screening for CRC a priority in their healthcare planning. Thus, Spain's Ministry
      of Health and Consumer Affairs included population screening for CRC in its National
      Healthcare Plan as a priority action within the Comprehensive Plan against Cancer (PICA),
      which was required to be implemented by the year 2007.

      The screening tools we currently have are not ideal either because, like the test for faecal
      occult blood (FOBT), which is the most evaluated to date, they are not sensitive enough or,
      like conventional colonoscopy, they are not risk-free. All of this means that population
      adherence is limited.

      In this study, we wish to compare two new diagnostic techniques for CRC (colon capsule and
      virtual colonoscopy) that, although recently introduced into the healthcare system, have
      sufficient scientific evidence to confirm that they are effective and possibly cost-effective
      techniques.

      The population we are concerned with in this study is the healthy population-men and women
      50-69 years of age with no significant history. Therefore, the screening method we offer must
      be the least invasive and the most comfortable method possible so that good compliance is
      achieved. This means techniques that are painless and essentially harmless in comparison with
      conventional colonoscopy. If we were to observe higher concordance between these techniques
      and conventional colonoscopy in terms of detecting lesions, we would use the latter strictly
      for therapeutic reasons in this population, thereby significantly reducing the complications
      associated with it.

      Objectives

      Main objectives:

        1. To demonstrate that virtual colonoscopy and colon capsule are effective CRC screening
           techniques in the intermediate risk population, with adenoma diagnostic rates comparable
           to conventional colonoscopy.

        2. To compare the diagnostic capabilities of the colon capsule and virtual colonoscopy with
           those of conventional colonoscopy with respect to the size and characteristics of the
           lesions (especially lesions that are flat or smaller than 6 mm).

        3. To analyse the population's participation rate for each screening strategy and identify
           the factors that influence participation (individual, family, and socioeconomic factors
           as well as those relating to the doctor or the diagnostic procedure).

      Secondary objectives:

        1. To evaluate the rate of minor and major complications for each screening strategy.

        2. To analyse the rate of false positives and false negatives for the colon capsule and
           virtual colonoscopy in comparison with conventional colonoscopy.

      Methodology Type of study Randomised, and controlled study.

      Study subjects

      Inclusion Criteria:

      The main objective in this study is compare two non-invasive techniques in the study of
      colorectal cancer. When we calculate the sample size we observed that we need more than 1000
      patients per group. In this moment this study is very expensive and it is not feasible. Our
      proposal is include population with a higher prevalence of lesions: individuals with positive
      FIT (fecal immunochemical test) in which the prevalence of lesions is 60%. In this case,
      sample size is reduced considerably.

      The eligible population will be men and women, 50-69 years old, with no known risk factors
      and positive FIT.

      Exclusion Criteria:

        1. Individuals who have symptoms suggestive of colorectal disease (rectorrhagia, change in
           bowel movement frequency, constitutional syndrome, anaemia).

        2. History of inflammatory bowel disease, colorectal polyposis, colorectal adenoma or CRC,
           and total or partial colectomy.

        3. History of familial adenomatous polyposis or other hereditary polyposis syndromes;
           hereditary colorectal cancer not associated with polyposis (diagnosed by the presence of
           germinal mutation in the DNA repair genes and/or by fulfilment of the Amsterdam II
           criteria);

        4. Severe co-morbidity that carries a poor short-term prognosis (disease with an average
           life expectancy of less than 5 years) or a chronic illness that involves significant
           limitation of physical activity.

        5. Contraindication to undergoing colon capsule or virtual colonoscopy.

      Study groups and randomisation:

      All patients recruited who meet the inclusion criteria will be randomised into the two study
      groups:

      Group I: Screening via virtual colonoscopy and subsequent conventional colonoscopy (within 1
      week). In this group of patients, performance of the conventional colonoscopy will be delayed
      to ensure that bowel preparation is comparable in the two study groups.

      Group II: Screening with colon capsule and subsequent conventional colonoscopy (within hours,
      since these patients will have already completed bowel preparation for the first screening
      test).

      When the conventional colonoscopy is done, pertinent therapeutic procedures will be
      performed, if necessary.

      Subsequently, the two groups of patients will be followed through visits to the hospital in
      which they will be instructed about the approach to follow from that time.

      Sample size When we calculate the sample size we observed that we need more than 1000
      patients per group. In this moment this study is very expensive and it is not feasible. Our
      proposal is include population with a higher prevalence of lesions: individuals with positive
      FIT (fecal immunochemical test) in which the prevalence of lesions is 60%. In this case,
      sample size is reduced considerably.

      Adenomas detection rate (ADR) in these patients with positive FIT in colonoscopy (gold
      standard) is 60% (NEJM 2012). We assume that colon capsule will detect the same number of
      lesions than gold standard, and a difference of 15% with virtual colonoscopy will be
      clinically significant. We will need 187 patients per group, with a significance level of 5%
      and a statistical power of 80%.

      The calculation was performed using the Study Size Granmo program.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        The population we are concerned with in this study is the healthy population-men and women
        50-69 years of age with no significant history. Therefore, the screening method we offer
        must be the least invasive and the most comfortable method possible so that good compliance
        is achieved. This means techniques that are painless and essentially harmless in comparison
        with conventional colonoscopy. If we were to observe higher concordance between these
        techniques and conventional colonoscopy in terms of detecting lesions, we would use the
        latter strictly for therapeutic reasons in this population, thereby significantly reducing
        the complications associated with it
      
Keywords: Colonoscopy, CT colonography, Colon capsule