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Cytosponge, biomarker panel predicts Barrett's progression
Using a non-endoscopic device touted as a “sponge-on-a-string” test, researchers were able to identify patients with Barrett’s esophagus who have a low risk for progression to esophageal cancer, allowing them to avoid endoscopic evaluation.
“This study is an important step toward being able to distinguish between patients at low and high risk for esophageal cancer in the GP setting,” Rebecca C. Fitzgerald, MD, from the MRC Cancer Unit at the University of Cambridge, U.K., told Healio Gastroenterology. “We have shown previously how we can detect the precancerous condition called Barrett’s esophagus using a very simple test.”
Rebecca C. Fitzgerald
This test, the Cytosponge (Covidien), consists of a pill on a string that is swallowed and retrieved 5 minutes later, collecting esophageal cells as it is withdrawn, Fitzgerald said. “The cell sample is then sent to a lab to do an antibody test (called TFF3) to detect Barrett’s. However, we know that most patients with Barrett’s will not develop cancer and therefore we need a way to separate those at low and high risk.”
Fitzgerald and colleagues therefore evaluated the risk for dysplasia status in 468 patients with Barrett’s esophagus and intestinal metaplasia who underwent the Cytosponge test before their surveillance endoscopy as part of the multicenter BEST2 cohort study.
The Cytosponge samples were tested for three protein biomarkers (P53, c-Myc and Aurora kinase A), two methylation markers (MYOD1 and RUNX3), glandular atypia and TP53 mutation status. Other factors, including age, waist-to-hip ratio and length of Barrett’s segment were included in the mathematical risk model.
Overall, 376 patients had no dysplasia and 22 had high-grade dysplasia or intramucosal adenocarcinoma.
Of the total cohort, 35% were determined to be low-risk (100% probability of being truly non-dysplastic; 0% probability of having high-grade dysplasia or intramucosal adenocarcinoma), 51% were determined to be moderate-risk (14% probability of high-grade dysplasia), and 12% were determined to be high-risk (13% probability of non-dysplastic endoscopic biopsies; 87% probability of high-grade dysplasia or intramucosal adenocarcinoma).
The validation cohort consisted of 51 non-dysplastic patients and 14 with high-grade dysplasia, of whom 38% were low-risk (96% probability of non-dysplastic). The moderate risk group included 27 non-dysplastic patients and eight with high-grade dysplasia, while 8% of the total cohort were high-risk and included no non-dysplastic cases and five with high-grade dysplasia.
“What this study shows is that we can use the very same cell sample tested for TFF3 to do a second stage test to see if the patient needs an endoscopy,” Fitzgerald said. “We have shown that one-third of patients can be accurately identified to be at very low risk and so spared endoscopy. This could save patients unnecessary endoscopy procedures with benefits for the patients and to the NHS.” – by Adam Leitenberger
Disclosures: Fitzgerald and two other researchers report they are named inventors on patents pertaining to the Cytosponge.