Efficacy of Fecal Immunochemical Test Using Digital Rectal Exam

Study Overview
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Brief Summary
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This study will investigate the use of digital rectal exam (DRE) to obtain stool samples for the fecal immunochemical test (FIT) in patients due for screening colonoscopy and in pre-operative patients with known colorectal cancer. FIT is currently FDA-approved for spontaneous stool and DRE, however, samples are not commonly obtained by DRE. In addition, some clinicians remain skeptical about the accuracy of FIT using stool obtained from DRE. This study aims to assess the correlation between FIT using the stool sample from DRE (FIT-DRE) and standard of care FIT (FIT-SOC). If good correlation is shown, the investigators may be able to demonstrate efficacy of FIT using a DRE in the clinic setting. This may help avoid logistical barriers, as well as improve compliance and adherence to colon cancer screening in the outpatient setting, eventually leading to improved quality of care.

Detailed Description
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Fecal immunochemical testing (FIT) is an FDA-approved stool-based screening test for colorectal cancer. It offers a less invasive colorectal cancer screening option for patients who are not agreeable to colonoscopy and measures the level of Ab-globin complexes in the stool without direct interference with diet or medications. FIT has been shown to be selective for colorectal bleeding, as globin from the upper GI tract is digested by proteolytic enzymes. A meta-analysis of studies analyzing FIT showed a pooled sensitivity of 0.79 (95% CI 0.69-0.86) and specificity was 0.94 (CI 0.92-0.95). In a large study comparing FIT with another stool-based screening test, gFOBT, sensitivity of FIT was found to be 0.53-0.73 for CRC and 0.20-0.25 for advanced neoplasia compared to gFOBT, which showed 33.3% for CRC and 8.6% for advanced neoplasia. In addition, FIT requires fewer stool samples and the lack of dietary or medication modifications. As a result, compliance is likely to be higher, which is crucial for cancer detection. A challenge inherent to stool-based screening tests is compliance with sample submission by the patients. FIT is meant to improve logistical barriers to screening because only one sample is needed, however, compliance rates with standard of care FIT (FIT-SOC) is approximately 50%. FIT using stool from a digital rectal exam (DRE) performed during a clinic visit may be an effective screening tool for patients preferring stool-based screening. FIT has been FDA-approved for the testing of spontaneously passed stool, as well as stool collected by DRE. Manufacturers of FIT have claimed that DRE provides a sufficient amount of stool for sampling, however, there are no validated studies to our knowledge which demonstrate adequate efficacy. As a result, FIT using DRE is not commonly done in clinical practice. This study aims to assess the correlation of FIT using DRE (FIT-DRE) with standard of care FIT (FIT-SOC) as a method of obtaining stool samples.

Official Title
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Efficacy of Fecal Immunochemical Test Using Digital Rectal Exam

Conditions
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Fecal Immunochemical Test

Intervention / Treatment
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* Device: FIT-SOC
* Device: FIT-DRE


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults between the ages of 50-75 who are due for colon cancer screening and scheduled for colonoscopy Preoperative patients with established diagnosis of colon cancer Exclusion Criteria: Patients with a diagnosis of Inflammatory Bowel Disease (IBD). Patients who are pregnant.

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: FIT-SOC<br>Fecal immunochemical test performed on spontaneously passed stool as noted in the standard instructions. | Device: FIT-SOC<br>* Study subjects will be given a standard kit for fecal immunochemical test by their primary healthcare provider. As per standard practice, the patient will take the kit home and use the included FIT applicator to collect a stool sample from spontaneously passed stool during a regular bowel movement. The patient will then mail the stool sample to the lab in a pre-paid envelope, which is provided in the kit.<br>|
| Experimental: FIT-DRE<br>Fecal immunochemical test completed with stool collected during digital rectal exam. | Device: FIT-DRE<br>* Study subjects will have a digital rectal exam completed by their primary care providers during the physical exam portion of a routine clinic visit. The stool collected on the examiner's finger will be applied to the FIT applicator in the standard kit, which will then be sent to the lab for processing.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concordance between standard FIT results and DRE FIT results. | For example, the percentage of positive standard FIT results that also have positive DRE FIT results, and the percentage of negative standard FIT results that also have negative DRE FIT results. | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Digital rectal exam, Colon cancer screening