Mayo Clinic Researcher Cites Positive Results for Cologuard-Style Liver Cancer Test
A prominent Mayo Clinic gastroenterologist who co-invented the Cologuard stool test for colorectal cancer now says he and his colleagues at Exact Sciences Corp. have also developed a highly accurate blood DNA test for detecting liver cancer.
Dr. John Kisiel, a consultant in Mayo’s gastroenterology and hepatology division and an assistant medical school professor, originally co-developed the cancer-detection method used in Cologuard, which was licensed to Madison, Wisconsin-based Exact Sciences under a 2009 scientific collaboration and venture capital investment.
Since then, Cologuard has become a highly successful consumer product, offering users an accurate, home-based method of detecting the early stages of colorectal cancer as an alternative to invasive and unpleasant colonoscopies performed at doctors’ offices. The unpopularity of colonoscopies has been blamed for stubbornly high rates of colon cancer which could have been prevented if screened for regularly.
The breakthrough technology searches for telltale DNA biomarkers in stool samples which users mail in to company’s Madison headquarters. It has been proven to be 94-percent sensitive in detecting early-stage colorectal cancer — a big improvement over an existing colonoscopy alternative called the fecal immunochemical test.
This month, meanwhile, Dr. Kisiel announced promising early results for the Exact Sciences/Mayo collaboration’s latest efforts to replicate the same kind of DNA biomarker testing for liver cancer in blood samples.
Speaking at the 2018 Digestive Disease Week conference, the world’s largest gathering of gastroenterologists and scientists in the field, Kisiel laid out the results of a novel panel of six DNA biomarkers in detecting hepatocellular carcinoma (HCC), the most common type of liver cancer.
The Mayo scientist said the panel was tested against 244 human blood samples which included 95 HCC samples, 51 with cirrhosis but no HCC, and 98 healthy controls. Much like Cologuard’s highly accurate results for detecting colorectal cancer, the HCC panel was found to have 95 percent overall sensitivity.
Perhaps most importantly, he added, sensitivity among patients with early, curable-stage disease was 91 percent, thus showing the potential to replicate Cologuard’s utility as an easy-to-use tool for cutting down the rate of preventable diseases.
Exact Sciences chief medical officer Graham Lidgard said in a company blog post that, like colorectal cancer, screening for HCC is becoming more imperative as instances of the disease grow due to the increase in risk factors such as obesity and cirrhosis of the liver caused by chronic hepatitis B or C infection.
“Monitoring of individuals prone to developing HCC is critical – if caught early, clinicians can treat HCC, offering patients improved outcomes,” he wrote. “The three-year survival rate for HCC nearly doubles in individuals who undergo regular surveillance.”
However, much like patient reluctance to undergo colonoscopies, adherence to a regular testing regimen for HCC is spotty at best. That’s because it involves a time-consuming process of undergoing an ultrasound exam and the measurement of the serum biomarker alpha-fetoprotein, or AFP. These cumbersome tests must be repeated every six to 12 months to be effective, and even then, are not very accurate.
Most at-risk patients, Lidgard added, “do not adhere to the surveillance. Liver ultrasound combined with AFF tests were found to detect only 63 percent of early-stage HCC. Performance varies because it is dependent upon the technician’s expertise and the patient’s body type. Clearly there is a need for a more sensitive and reliable test.”