Blood-Based Test Could Help ID Hard-to-Detect Gastrointestinal Cancers
By Denise Baez
SAN FRANCISCO -- January 24, 2020 -- A blood-based screening test that uses cell-free DNA (cfDNA) to identify methylation signals of hard-to-detect gastrointestinal (GI) cancers could potentially help detect cancer at earlier stages, according to a study presented here at the 2020 Gastrointestinal Cancers Symposium (ASCO-GI).
“The potential of this test is to diagnose cancer earlier when it’s more treatable -- the ability to do that across cancer types could be quite valuable,” said Brian M. Wolpin, MD, Dana Farber Cancer Institute, Boston, Massachusetts. “Many of the cancer types that this test detects don’t currently have screening tests that allow earlier cancer detection before the cancers cause symptoms.”
The Circulating Cell-free Genome Atlas (CCGA) study included individuals with and without cancer. Cancers included 67 cases of oesophagus or stomach cancer, 95 cases of pancreatic, gallbladder or extrahepatic bile duct cancer, 29 cases of liver or intrahepatic bile duct cancer, and 121 cases of colorectal cancer.
Plasma cfDNA was subjected to a cross-validated targeted methylation sequencing assay. Methylation fragments were combined across targeted genomic regions and assigned a probability of cancer and a predicted tissue of origin (TOO).
Detection across all GI cancers was 82% at a >99% pre-set specificity. Overall accuracy for locating the specific region of the cancer within the GI tract was 92%.
When broken down according to cancer type, detection was 85% for upper GI cancers, 82% for pancreas/gallbladder/extrahepatic bile duct cancers, 86% for liver/intrahepatic bile duct cancers, and 79% for colon/rectum cancers. Predicted TOO accuracy was 87%, 92%, 78%, and 98%, respectively.
“The data show that evaluating methylation of cell-free DNA within a blood sample, may detect a variety of gastrointestinal cancers with good sensitivity and with a low rate of false positives,” said Dr. Wolpin. “If further validated with additional testing, this approach has the potential to allow us to diagnose gastrointestinal cancers earlier, when they’re more treatable.”
The 2020 Gastrointestinal Cancers Symposium is sponsored by the American Gastroenterological Association, the American Society of Clinical Oncology, the American Society for Therapeutic Radiation Oncology, and the Society of Surgical Oncology.
[Presentation title: Performance of a Blood-Based Test for the Detection of Multiple Cancer Types. Abstract 283]