Detecting and preventing esophageal cancer may soon become easier thanks to a pair of clinical trials overseen in part by University of Colorado Cancer Center member Sachin Wani, MD.
Wani, the endowed chair of the Katy O. and Paul M. Rady Esophageal and Gastric Center of Excellence and a professor of gastroenterology in the Department of Medicine at the CU School of Medicine, is co-investigator and site principal investigator on a five-year National Cancer Institute (NCI) grant to conduct clinical trials on a non-endoscopic method of detecting the precancerous condition known as Barrett’s esophagus. In the EsoGuard test, an uninflated balloon is swallowed, then inflated by a clinician to collect cells from the lower esophagus. The cells are then DNA-tested for the presence of Barrett’s.
“The unfortunate reality is that patients who are at risk for Barrett’s esophagus often don't get adequately screened,” Wani says. “One of the biggest limitations is the fact that the screening often requires an endoscopy, which is an invasive test that requires sedation. More than 90% of our patients with esophageal cancer have no prior diagnosis of this precancerous condition, which reflects the fact that they've never been screened. That's what we're trying to change.”
Expanding the testing population
Currently, Wani says, people are only tested for Barrett’s esophagus if they have acid reflux symptoms that have been ongoing for five years or have significant reflux on a weekly basis. The EsoGuard technology will allow wider screening of those with risk factors for the condition — including age greater than 50, obesity, tobacco use, and a family history of Barrett's or esophageal cancer — without the need for a costly and time-consuming endoscopy.
“We know that esophageal cancer can develop in these individuals as well,” Wani says. “So we're going to evaluate this platform to see how well it performs in individuals who are at risk for esophageal cancer but don't necessarily have the classic reflux symptoms.”
A simple test
During the clinical trial, the EsoGuard test will be administered by Wani and his research team, and all participants will receive an endoscopy to determine the accuracy of the method. In the future, however, he foresees the five-minute balloon test being administered in-office by a general physician.
“It's basically a balloon that's inverted into a small capsule, which is the size of a vitamin pill, and it's attached to a string,” he says. “You swallow this capsule, and once it’s in the stomach, the physician uses a syringe to inflate the balloon, then pulls it through the lower part of your esophagus. Once that’s done, the physician deflates the balloon, brings it back into the capsule, then removes it.
“By doing that, we selectively sample the area where you find Barrett’s, which is in the lower part of the esophagus,” Wani continues. “Then we check for methylation markers that are associated with the presence of Barrett's esophagus.”
Patients who test positive in that scenario would then receive an endoscopy to verify the findings. But those who test negative would need no further testing, he says.
Showing that BAD is good science
In addition to the EsoGuard trial, the NCI grant also supports the further development of a deep DNA sequencing and AI analysis protocol known as BAD for detecting esophageal cancer DNA. Wani and researchers at other trial sites hope to use BAD testing to identify individuals at high risk for developing esophageal cancer and to adapt the system — which currently gathers samples by using a device to brush cells from the lining of the esophagus — to work with samples gathered by the EsoGuard device.
“Not all patients with Barrett's progress to esophageal cancer, but the critical question is, ‘Who with Barrett’s esophagus is likely to progress, and can we intervene on those patients sooner rather than later?’” Wani says. “That's the whole concept of this study.”
