Assessing the Effect of a Blood-based Colorectal Cancer Screening Test on Screening Adherence and Colonoscopy Completion

Overview

Objectives: Colonoscopy and stool-based testing are the two predominant colorectal cancer (CRC) screening tests used in the US, and both reduce colorectal cancer mortality. However, only 62% of Americans are up to date with screening, partly because many individuals find these two tests inconvenient or unacceptable for a variety of reasons. There is an unmet need for a non-invasive test that does not require bowel preparation or handling stool, and the Septin9 DNA blood test may be an alternative for those individuals who would otherwise remain unscreened. Aims: Aim 1: To measure screening uptake with a blood test in screen-resistant patients who have declined both colonoscopy and fecal immunochemical testing (FIT) at the Manhattan VA Medical Center * Sub-Aim 1a: To assess the proportion of those with a positive blood-based screening test who undergo diagnostic colonoscopy * Sub-Aim 1b: To describe the endoscopic findings on diagnostic colonoscopy Aim 2: To survey screen-resistant patients to understand their beliefs and attitudes about colorectal cancer screening and testing options We hypothesize that a substantial proportion of patients who have refused colonoscopy and FIT will accept the blood test. We hypothesize this will be driven by the convenience of the blood test. Methods: This will be randomized controlled trial of individuals who have refused colonoscopy and FIT within past 6 months. Eligible patients will be randomized 1:1 to the intervention or control group. Both groups will be invited to participate in navigated colonoscopy or FIT by letter and telephone call. The intervention group will also be invited to participate in the blood test if they refuse colonoscopy and FIT. We will enroll 180 participants in each group (total n=360).

The proposed study is a randomized controlled trial that will 1) assess the uptake of a CRC screening blood test among patients who have declined both colonoscopy and FIT in the previous 6 months, including diagnostic evaluation of positive results and 2) survey patients about their beliefs and attitudes regarding CRC screening and testing options. All participants will be primary care patients at the Manhattan VA Medical Center. Based on a recent internal audit, there were 1502 patients who had at least one primary care visit from August 2016 through August 2017 and were not up to date with CRC screening. Up-to-date CRC screening is defined as either 1) a colonoscopy within the past 10 years or 2) FIT within the past year. We will perform an updated CRC screening audit at the beginning of the study to obtain the entire pool of eligible patients who are not up to date with screening. Eligible patients will then be randomized 1:1 to either an intervention group or a control group. All patients will receive a letter noting that they are not up-to-date on screening and encouraging them to contact a study number if they choose to screen with colonoscopy or FIT. Patients who call will speak to a research assistant who is trained in patient navigation and can facilitate referrals for colonoscopy or FIT. Following the sequential testing approach, letters addressed to the intervention group will also include an option to participate in the blood test, with instructions to call the study number to schedule the blood draw. In addition to the letter, both groups will also receive a follow-up telephone call that reiterates information in the letter. The research assistant will make and receive all calls using a standard script. All patients will also be asked to complete a survey about their beliefs and attitudes regarding CRC screening. The survey will be mailed with the invitation letter and will also be administered over the telephone by the research assistant. The study team will notify patients and their primary care physicians of blood test results and will facilitate a colonoscopy referral for those with positive tests. Primary care physicians will not be asked to notify the patients or make the colonoscopy referral because most will not have adequate knowledge of the Septin9 test to provide appropriate patient education. Participants who are randomized to the blood test arm will undergo phlebotomy, which will be performed by the study research assistant. The blood sample will be temporarily stored on-site and then transported to an off-site commercial laboratory (Lenco Diagnostic Laboratory, Brooklyn, NY) to run the assay. Clinical outcomes for both the intervention and control group participants will be measured as a secondary outcome. This includes timing and result of a screening colonoscopy or FIT for individuals in the controls group as well as diagnostic colonoscopy for participants who had a positive blood test.