Endoscope With Oxygen Sensor Detects Pancreatic Cancer
Mayo Clinic researchers see hope for earlier detection
An optical blood oxygen sensor attached to an endoscope is able to identify pancreatic cancer in patients via a simple endoscopic procedure, according to researchers at the Mayo Clinic in Jacksonville, Florida.
The study, published in GIE: Gatrointestinal Endoscopy, shows that the device, which acts like the well-known clothespin-type finger clip used to measure blood oxygen in patients, has a sensitivity of 92% and a specificity of 86%.
That means, of 100 patients with pancreatic cancer, the sensor would detect 92 of them, based on the findings. And of 100 patients who don’t have pancreatic cancer, the test would correctly identify them 86% of the time.
The device measures changes in blood flow in tissues that are in proximity to the pancreas, under the theory that tumors change the flow of blood in surrounding tissues because the tumors need oxygen to grow. The endoscope is passed into the stomach and the duodenum, where the measurements are taken. The pancreas lies just outside the duodenum.
To test the ability of the sensor to recognize pancreatic cancer, the researchers studied 14 patients with the disease and 10 cancer-free subjects.
“Although this is a small pilot study, the outcome is very promising,” said senior investigator Michael Wallace, MD, MPH. “There is no test now available that can accurately identify pancreatic cancer at an early stage, short of removing some of the organ. We need new ways to detect pancreatic cancer effectively, and simply, as early as possible.”
Currently, more than 90% of pancreatic cancers are discovered at an advanced or metastatic stage, with no effective therapy available. That explains why pancreatic cancer is the fourth most common cause of cancer deaths in the U.S., although it ranks 10th in occurrence.
The new technique is a different way of looking at cancer detection, Wallace says.
“What is quite unusual is that we were trying to sense changes that are not in the tumor itself but are in the nearby, normal-appearing tissues,” he commented. “It relies on a principle, now being increasingly acknowledged, called a cancer field effect. Instead of looking for the needle in the haystack, we now look at the haystack to see how it is different when there’s a needle inside.”
“The general concept is that cancers cause surrounding tissue to undergo changes in the flow of oxygen that are detectable, not visually or even under the microscope, but by this kind of sensor,” he said. Wallace says the blood-sensor endoscope is also being tested in colon and esophageal cancers.
Source: EurekAlert; June 6, 2014.