It might also reduce colonoscopies by an estimated 15%-41%.
The greatest reduction would likely be achieved by annual FIT-based surveillance, especially with FIT FOB-Gold at a threshold of at least 32 µg/g feces, according to findings from the Dutch MOCCAS study published in Gastroenterology.
In this cross-sectional observational study, the multitarget DNA test outperformed FIT for detecting advanced precursor lesions, especially serrated polyps. According to long-term-impact mathematical modeling, however, DNA-based surveillance would be more costly than colonoscopy surveillance, whereas FIT would save costs.
“With the worldwide implementation of FIT-based screening programs, following a positive test, many more people enter surveillance programs after polypectomy. This results in an increased pressure on the colonoscopy capacity and healthcare budgets,” lead author Beatriz Carvalho, PhD, a molecular biologist in the Department of Pathology of the Netherlands Cancer Institute in Amsterdam, said in an interview.
Netherlands Cancer Institute
Dr. Beatriz Carvalho
A noninvasive strategy could ease the surveillance burden on healthcare resources and be more palatable to patients. Post-polypectomy guidelines have already been relaxed to allow less intensive surveillance.
“Our working hypothesis was that although the sensitivity of a singular molecular test to detect CRC or advanced adenomas is lower than that of colonoscopy, repeating molecular stool testing would yield similar detection rates as colonoscopy-based surveillance. And our hypothesis was confirmed,” Carvalho said.
The results of the MOCCAS study align with those of other studies that found that FIT could be safely applied as a triage test in post-polypectomy surveillance and could safely extend the interval of surveillance colonoscopy. “But these studies did not include a long-term impact analysis,” she said. “The next step is to run a prospective interventional study to validate the MOCCAS findings.”
Offering an outsider’s perspective on the findings, Uri Ladabaum, MD, director of the Gastrointestinal Cancer Prevention Program and a professor of medicine at Stanford University School of Medicine in Palo Alto, California, said the real-world results on lesion detection and the multi-year-horizon modeling performed are provocative and point to the potential to base post-polypectomy surveillance on stool tests.
Stanford University
Dr. Uri Ladabaum
He cautioned, however, that the proposed paradigm requires the ability to deploy FIT-based surveillance with broad flexibility in relation to hemoglobin-detection thresholds and testing interval, depending on the specific FIT that is chosen, with the possibility these may differ by setting based on the characteristics of the population and the relevant epidemiology.
“Such flexibility may or may not be technically feasible in all settings — for instance, in the current US regulatory context, it would be challenging to implement FIT-based testing at newly adjusted detection thresholds,” he said.
Nevertheless, the study provides a strong rationale for a real-world study of FIT-based surveillance, he added. “The choice of specific FIT and detection threshold will be critical. Multiple rounds of FIT-based surveillance, that is, years of prospective surveillance, will be needed to constitute a properly designed comparison with surveillance colonoscopy.”