Stool-Based DNA Testing Leads to Timely Colonoscopy

Colorectal cancer (CRC) remains a leading cause of cancer deaths in the US, yet many patients delay colonoscopy due to hesitancy and long wait times. Long follow-up intervals after stool-based testing could further exacerbate health disparities in rural patients who already face significant barriers to health care. Now, a new observational study has shown that stool-based DNA testing can provide timely follow-up for both rural and urban patients and thus help increase equitable CRC screening.

The observational case–control analysis by researchers from the University of North Dakota (Grand Forks, ND, USA) included 1316 patients 18 years or older who had a positive DNA-based stool test and subsequently underwent diagnostic colonoscopy between January 2018 and December 2023. Participants were categorized as rural or nonrural using Rural-Urban Commuting Area codes, and the primary outcome was days from a positive stool test to diagnostic colonoscopy.

Image: The study found rural and nonrural patients have similar follow-up times after positive stool-based DNA tests (Photo courtesy of 123RF)

Of the 1,316 patients included, 668 (50.8% were classified as rural; the median time to diagnostic colonoscopy was similar between groups — 35 days for rural patients versus 37 days for nonrural patients (P=.6). Rural patients were significantly more likely to have their colonoscopy performed at an external facility (25% vs 3.1%; P<.001), despite comparable timeliness. In their research published in The American Surgeon, the authors note limitations, including reliance on recorded data and that the analysis focused only on patients who completed both stool testing and colonoscopy.

The investigators concluded that the findings support stool-based DNA testing as a tool to increase screening access and deliver timely diagnostic follow-up across geographic settings. At the study institution, the results informed plans to use stool-based testing for all low-risk patients, helping to stratify who needs diagnostic colonoscopy versus ongoing noninvasive monitoring. Broader adoption of stool-based testing could reduce missed diagnoses, shorten time to treatment, and help close rural–urban screening gaps.

“With all patients receiving colonoscopy in our system, patients had an average wait time of 1 year from initial contact to colonoscopy,” wrote the researchers. “It is also more accessible for many patients and helps stratify low-risk individuals, identifying those who require diagnostic colonoscopy vs. those who can be adequately monitored with stool-based testing alone.”