Mayo Clinic researchers have demonstrated that a noninvasive screening test can detect not only colorectal cancer but also the common cancers above the colon — including pancreas, stomach, biliary and esophageal cancers. This is one of more than 100 Mayo Clinic studies presented at Digestive Disease Week 2009 in Chicago, May 30–June 4.
“Patients are often worried about invasive tests like colonoscopies, and yet these tests have been the key to early cancer detection and prevention,” says David Ahlquist, M.D., Mayo Clinic gastroenterologist and lead researcher on the study. “Our research team continues to look for more patient-friendly tests with expanded value, and this new study reveals an opportunity for multi-organ digestive cancer screening with a single noninvasive test.”
The researchers studied 70 patients with cancers throughout the digestive tract. Besides colon cancer, the study looked at throat, esophagus, stomach, pancreatic, bile duct, gallbladder and small bowel cancers to determine if gene mutations could be detected in stool samples. Using a stool test approach developed at Mayo Clinic, researchers targeted DNA from cells that are shed continuously from the surface of these cancers. Also studied were 70 healthy patients. Stool tests were performed on cancer patients and healthy controls by technicians unaware of sample source. The stool DNA test was positive in over 70 percent of digestive cancers, but remained negative for all healthy controls, thus demonstrating the approach’s feasibility.
Stool DNA testing detected cancers at each organ site, including 65 percent of esophageal cancers, 62 percent of pancreatic cancers, and 75 percent of bile duct and gallbladder cancers. In this series, 100 percent of both stomach and colorectal cancers were detected. Importantly, stool test results did not differ by cancer stage; early-stage cancers were just as likely to be detected as late-stage cancers.
“It’s very exciting to see this level of sensitivity for digestive cancer detection in our first look at this test application,” says Dr. Ahlquist, “Historically, we’ve approached cancer screening one organ at a time. Stool DNA testing could shift the strategy of cancer screening to multi-organ, whole-patient testing and could also open the door to early detection of cancers above the colon which are currently not screened. The potential impact of this evolution could be enormous.”
Below is a link to an edited youtube video with Dr. Ahlquist.