Stool DNA Analysis Cost-effective Check for Colon Cancer in Ulcerative Colitis Patients

Stool DNA Analysis Cost-effective Check for Colon Cancer in Ulcerative Colitis Patients

A recent study indicated that while colorectal cancer (CRC) surveillance in patients with ulcerative colitis was generally cost effective, the addition of stool DNA analysis to surveillance colonoscopy was the most cost-effective approach.

If a stool DNA test is positive, then a colonoscopy would be performed, the researchers said.

The study, “Stool DNA Analysis is Cost Effective for Colorectal Cancer Surveillance in Patients with Ulcerative Colitis,” was published in the journal Clinical Gastroenterology and Hepatology.

Surveillance colonoscopy has been considered standard of care for ulcerative colitis patients, based on observational (non-randomized) studies showing reduced incidence of colorectal cancer and earlier stage of CRC detected by this practice,”  Dr. John B. Kisiel, MD, of the division of gastroenterology and hepatology at the Mayo Clinic in Rochester, Minnesota, said in a press release.

However, patient compliance with “frequent and invasive” colonoscopies is not high, and “perhaps as low as 50 percent” in some instances, Kisiel said. “Additionally, modelling studies of surveillance colonoscopy by either white light exam or chromoendoscopy techniques have reached conflicting results on cost-effectiveness.”

A screening colonoscopy is performed when there are no signs or symptoms of problems. A surveillance colonoscopy is recommended once a patient has had colon polyps, colon cancer, or other gastrointestinal disease.

Patients with chronic ulcerative colitis (UC) have an increased risk for developing colorectal neoplasia. To reduce this risk, surveillance using white-light endoscopy (WLE) or chromoendoscopy are options, but they are underused. Analysis of DNA from stool samples (sDNA) has been shown to be a sensitive detection approach, but researchers weren’t sure whether it was cost-effective.

Kisiel and his colleagues assessed whether the multi-target stool DNA test Cologuard is a cost-effective strategy for CRC surveillance in ulcerative colitis patients, which may increase patient compliance. Cologuard assays mutant KRAS, methylated BMP3, methylated NDRG4, and a fecal immunochemical test.

Researchers adapted a previously published Markov model to simulate the clinical course of chronic ulcerative colitis, cancer, or dysplasia, and the costs and benefits of care with four surveillance strategies. The new model had “inputs on stool DNA performance and new parameters from the recent scientific literature showing the benefits of surveillance testing,” Kisiel said.

The four surveillance strategies were: sDNA and diagnostic chromoendoscopy for positive sDNA tests, sDNA and white light endoscopy for positive sDNA tests, chromoendoscopy with targeted biopsies, or white light endoscopy with random biopsies.

Costs were based on 2014 Medicare reimbursements. The primary outcome was the incremental cost-effectiveness ratio (incremental cost/incremental difference in quality-adjusted life years) compared with no surveillance and a willingness to pay threshold of $50,000 per quality adjusted life year.

“We were surprised to find that all the surveillance options were cost-effective,” Kisiel said. “Additionally, the lowest costs per quality adjusted life years were shown for surveillance strategies that began with stool DNA and used colonoscopy only to evaluate positive stool tests. Among colonoscopy techniques, chromoendoscopy appeared more cost-effective than white light.”

The researchers found that the incremental cost effectiveness ratios were $16,362 per quality adjusted life year for sDNA with diagnostic chromoendoscopy, $18,643 for sDNA with diagnostic white light endoscopy, $23,830 for chromoendoscopy alone, and $27,907 for white light endoscopy alone.

Results showed that all approaches dropped under the willingness to pay threshold at two-year intervals. They also revealed a higher cost effectiveness of sDNA with diagnostic chromoendoscopy versus chromoendoscopy alone, up to $1,135 per sDNA test.

In addition, the researchers found that at all rates of patient compliance, sDNA analysis was cost effective, and unless the precision of sDNA analysis fell below 65 percent, combining sDNA with diagnostic chromoendoscopy was preferred over chromoendoscopy alone.

“These findings are important because they support the small but growing body of evidence of benefit for CRC surveillance in UC patients and suggest an important potential role for stool DNA in this practice,” Kisiel said.