Small intestine is gateway to early detection of pancreatic cancer
A minimally invasive endoscopic technique detected pancreatic cancer 100% of the time in a small study conducted at the Mayo Clinic campus in Jacksonville, Florida. The technique, called polarization gating spectroscopy, uses a tiny light probe that shines within the small intestine to measure changes in cells and blood vessels produced by a cancer growing in the adjoining pancreas.
Pancreatic cancer is usually detected by means of an imaging scan followed by a biopsy. Tumors discovered through these methods are usually at an advanced stage. Because the pancreas is located so deep in the abdomen, surrounded by intestines, Mayo Clinic gastroenterologist Michael B. Wallace, MD, and colleagues theorized that the much more accessible tissue of the small intestine might reflect changes that signaled cancer in the pancreas.
The Mayo team used a light probe developed by their collaborators at Northwestern University in Chicago, Illinois, to measure the amount of oxygenated blood and blood vessel diameter in tissue near the duct that joins the pancreas to the small intestine. Normal tissue in the vicinity of cancer reveals changes in the amount of oxygen in the blood and evidence of enlarged blood vessels.
Using the probe on 10 patients who were later determined to have pancreatic cancer and on nine who did not, Wallace's team found that testing both measures—blood oxygenation and blood vessel diameter—detected all 10 pancreatic cancers. However, the probe was only 63% accurate in determining which of the healthy volunteers did not have the disease.
While acknowledging that the instrument could be improved, Wallace noted in a statement issued by Mayo Clinic that if additional research confirms early results, “It would make the pancreas accessible to a much simpler upper endoscope, and that would be a real advance in the treatment of pancreatic cancer.”
According to Wallace, such “field effects” from cancer can be measured in other areas of the GI tract. “With this technology, other studies have shown that cancerous polyps can be detected more than 11 inches from the polyp itself,” he pointed out, adding that early studies are evaluating whether esophageal cancers can also be detected remotely.
Wallace presented his group's results at the Digestive Disease Week 2012 meeting, held May 19 through May 24 in San Diego, California. The polarization gating spectroscopy technique will now be tested in a much larger international clinical trial led by Mayo Clinic researchers.