Exact Sciences Corp., a provider of cancer screening and diagnostic tests, in collaboration with Mayo Clinic Comprehensive Cancer Center, reported on data showing high sensitivity and specificity for the non-endoscopic Oncoguard Esophagus test that is currently in development for the detection of esophageal adenocarcinoma (EAC) and its precursors, including Barrett’s esophagus (BE).(1,2) 

Findings from the test’s algorithm training and testing were recently published in the Clinical Gastroenterology and Hepatology journal.

Screening for Esophageal Adenocarcinoma 

Esophageal adenocarcinoma is the most common form of esophageal cancer in the U.S. with incidence having increased significantly over the past few decades compared to other, more common types of cancer where rates have either declined or remained flat due to advanced technologies in screening.(3,4) The majority of EAC cases are diagnosed in advanced stages, with early EAC typically having no signs or symptoms, making screening in high-risk populations a critical need.(5) There are approximately 30 million people in the U.S. who are at high-risk for EAC and should be screened.(6)

“Esophageal adenocarcinoma (EAC) is quickly becoming one of the deadliest cancers, with over 80% of patients dying within five years of diagnosis.(7) Barrett’s esophagus (BE) is the only known precursor to EAC and patients with BE have an increased risk of progressing to EAC if not caught early. Standard methods of screening can be invasive and costly for patients, which is why there has been a recent push to change the screening guidelines to include non-endoscopic tests,” says Prasad G. Iyer, MD, Professor of Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic Comprehensive Cancer Center. “In collaborating with Exact Sciences, we are able to study the potential of a minimally invasive, non-endoscopic screening tool currently in development in patients at higher risk for EAC. Our algorithm training and testing study accomplishes the next critical step for the accurate, non-endoscopic detection of BE/EAC.”

Further reading: Exact Sciences Launches Hereditary Cancer Test

Study Results of Non-endoscopic Oncoguard Esophagus Test 

The study used an encapsulated sponge collection device to collect esophageal specimens from 352 participants in the training set and 125 participants in the test set. These were then blindly assayed for methylated DNA markers (MDMs). Cross-validation of the three-MDM panel demonstrated an overall sensitivity of 82% (CI, 68% to 94%) for BE detection at 90% specificity (CI, 79% to 98%) in the training set and 88% sensitivity (CI, 78% to 94%) at 84% specificity (CI, 70% to 93%) in the test set. In both training and test sets, sensitivity was 100% for EAC and BE with high grade dysplasia (HGD) – both treatment-eligible subsets. The collection method was generally well tolerated by study participants and was conducive to office-based implementation.

“In esophageal cancer, earlier screening and detection will provide an important advance, as we have seen in other cancers. While many experts recommend that people with chronic reflux disease and at least one other risk factor be screened for Barrett’s esophagus, only a small number of eligible patients undergo screening currently,”(8) says Paul Limburg, chief medical officer of Screening, Exact Sciences. “At Exact Sciences, our work has always focused on the latest innovations in screening and testing to help patients and clinicians have accurate, less invasive, and cost-effective options. We are collaborating with Mayo Clinic to continue the development of the Oncoguard Esophagus test as a minimally invasive solution for earlier detection of EAC and its precursors.”

The Oncoguard Esophagus test is currently under development and features of the test described above are outlining current development goals. This test has not been cleared or approved by the U.S. Food and Drug Administration (FDA) or any other national regulatory authority.


  1. Iyer, P. G., Taylor, W. R., et al. Highly Discriminant Methylated DNA Markers for the Non-endoscopic Detection of Barrett’s Esophagus. Am J Gastroenterol 2018, 113 (8), 1156-1166.
  2. Iyer, P. G.,Taylor, W. R., et al. Accurate Nonendoscopic Detection of Barrett’s Esophagus by Methylated DNA Markers: A Multisite Case Control Study. Am J Gastroenterol 2020, 115 (8), 1201-1209.
  3. Cook D, et al. Gastrointest Endosc Clin N Am. 2021 Jan; 31(1): 1–26. Accessed 26 March 2024. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7887893/
  4. He H, et al. Thorac Cancer. 2020 May; 11(5): 1121–1128. Accessed 26 March 2024. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7180574/
  5. Then T E, et al. World J Oncol. 2020 Apr; 11(2): 55–64. Accessed 26 March 2024.
  6. Chandar, A.K., Low, E.E., et al. Estimated Burden of Screening for Barrett’s Esophagus in the United States. Gastroenterology. Volume 165, Issue 1, p283-285.E2, July 2023.
  7. National Cancer Institute. Cancer Stat Facts: Esophageal Cancer. Accessed 26 March 2024.
  8. Eluri S, et al Am J Gastroenterol. 2022 Nov 1; 117(11): 1764–1771. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9633338/