Non-Invasive Stool Test May Detect Early-Stage GI Cancers 

SPECIAL REPORT—Gastrointestinal (GI) cancers account for approximately one in four cancer deaths.  While with today’s medical technology, most GI cancers have a relatively high cure rate; only colorectal cancer is regularly screened and diagnosed in time for successful treatment. People given the news that they have cancer of the pancreas or bile duct usually receive the diagnosis too late to be successfully treated.


Now, however, researchers from Mayo Clinic have demonstrated the ability to induce a noninvasive screening test that can detect colorectal cancer and cancers occurring higher in the GI tract including: pancreas, stomach, biliary and esophageal cancers.


While the most common diagnostic tool for detecting early-stage colorectal cancer is the colonscopy, the procedure remains invasive and some patients simply avoid the test even when persistent symptoms would suggest a need for it. 


Researchers at Mayo Clinic are studying the use of DNA-derived, non-invasive testing that can detect lesions and cancer throughout the GI tract. The most recent published study examined 70 patients with cancers throughout the digestive tract. Besides colon cancer, researchers looked at throat, esophagus, stomach, pancreatic, bile duct, gallbladder and small bowel cancers to determine if it were possible to obtain detection of malignant cells through the use of stool samples. 


Using a stool sample test developed at Mayo Clinic, took samples from those 70 patients with known GI cancers and also from 70 patients known to be healthy and cancer-free. Technicians performed testing on all patients without knowledge of the sample sources. The study found that the stool DNA test was positive in nearly 70 percent of digestive cancers but remained negative for all healthy controls. The results demonstrated to researchers that the testing could be feasible for screening purposes.


“Patients are often worried about invasive tests like colonscopies, and yet these tests have been the key to early cancer detection and prevention,” said 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.”


Researchers hope to continue developing the DNA-testing to further improve its accuracy, processing speed and ease of patient usage and affordability. “We anticipate that next generation tests will also be able to predict the tumor site, which will help physicians direct diagnostic studies and minimize unnecessary procedures,” says Ahlquist.


Other researchers from Mayo Clinic include: Hongzhi Zou, M.D., Ph.D; Jonathan Harrington; William Taylor; Mary Devens; Xiaoming Cao, M.D.; Russell Heigh, M.D.; Yvonne Romero, M.D.; Suresh Chari, M.D.; Gloria Petersen, Ph.D.; Lewis Roberts, M.B.Ch.B., Ph.D.; Jan Kasperbauer, M.D.; Julie Simonson; David I. Smith, Ph.D.; and Thomas Smyrk, M.D. 


Mayo Clinic's Division of Gastroenterology and Hepatology has been ranked #1 in the U.S. News & World Report Honor Roll of Top Hospitals since the rankings began 19 years ago.