Background & aims: Colorectal cancer (CRC) and advanced precancers can be detected noninvasively by analyses of exfoliated DNA markers and hemoglobin in stool. Practical and cost-effective application of a stool DNA-based (sDNA) test for general CRC screening requires high levels of accuracy and high-capacity throughput. We optimized an automated sDNA assay and evaluated its clinical performance.
Methods: In a blinded, multicenter, case-control study, we collected stools from 459 asymptomatic patients before screening or surveillance colonoscopies and from 544 referred patients. Cases included CRC (n = 93), advanced adenoma (AA) (n = 84), or sessile serrated adenoma ≥1 cm (SSA) (n = 30); controls included nonadvanced polyps (n = 155) or no colonic lesions (n = 641). Samples were analyzed by using an automated multi-target sDNA assay to measure β-actin (a marker of total human DNA), mutant KRAS, aberrantly methylated BMP3 and NDRG4, and fecal hemoglobin. Data were analyzed by a logistic algorithm to categorize patients as positive or negative for advanced colorectal neoplasia (CRC, advanced adenoma, and/or SSA ≥1 cm).
Results: At 90% specificity, sDNA analysis identified individuals with CRC with 98% sensitivity. Its sensitivity for stage I cancer was 95%, for stage II cancer it was 100%, for stage III cancer it was 96%, for stage IV cancer it was 100%, and for stages I-III cancers it was 97% (nonsignificant P value). Its sensitivity for advanced precancers (AA and SSA) ≥1 cm was 57%, for >2 cm it was 73%, and for >3 cm it was 83%. The assay detected AA with high-grade dysplasia with 83% sensitivity.
Conclusions: We developed an automated, multi-target sDNA assay that detects CRC and premalignant lesions with levels of accuracy previously demonstrated with a manual process. This automated high-throughput system could be a widely accessible noninvasive approach to general CRC screening.
Keywords: AA; BMP3; CRC; Colon Cancer; Early Detection; FIT; HGD; Hb; NDRG4; QuARTS; SSA; advanced adenoma; colorectal cancer; fecal immunochemical test; hemoglobin; high-grade dysplasia; quantitative allele-specific real-time target and signal amplification; sDNA; sessile serrated adenoma ≥1-cm size; stool DNA.
Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.