Plasma Septin9 versus Fecal Immunochemical Testing for Colorectal Cancer Screening: A Prospective Multicenter Study

Background: Screening improves outcomes related to colorectal cancer (CRC); however, suboptimal participation for available screening tests limits the full benefits of screening. Non-invasive screening using a blood based assay may potentially help reach the unscreened population. Objective: To compare the performance of a new Septin9 DNA methylation based blood test with a fecal immunochemical test (FIT) for CRC screening. Design: In this trial, fecal and blood samples were obtained from enrolled patients. To compare test sensitivity for CRC, patients with screening identified colorectal cancer (n = 102) were enrolled and provided samples prior to surgery. To compare test specificity patients were enrolled prospectively (n = 199) and provided samples prior to bowel preparation for screening colonoscopy. Measurements: Plasma and fecal samples were analyzed using the Epi proColon and OC Fit-Check tests respectively. Results: For all samples, sensitivity for CRC detection was 73.3 % (95 % CI 63.9–80.9%) and 68.0 % (95 % CI 58.2–76.5%) for Septin9 and FIT, respectively. Specificity of the Epi proColon test was 81.5 % (95 % CI 75.5–86.3%) compared with 97.4 % (95% CI 94.1–98.9%) for FIT. For paired samples, the sensitivity of the Epi proColon test (72.2 % –95 % CI 62.5–80.1%) was shown to be statistically non-inferior to FIT (68.0%–95 % CI 58.2–76.5%). When test results for Epi proColon and FIT were combined, CRC detection was 88.7 % at a specificity of 78.8%