“Blood tests that can identify cancer in asymptomatic individuals, particularly GI cancers that can be difficult to detect in early stages, could change cancer diagnostics by making it easier to accurately screen for and identify these cancers earlier. The preliminary results seen in this study, however, will need to be validated by screening large populations of asymptomatic individuals,” said ASCO Expert Muhammad Shaalan Beg, MD.
ALEXANDRIA, Va. – A blood-based screening test using cell-free DNA to identify methylation signals of hard-to-detect gastrointestinal (GI) cancers that could potentially help detect cancer at earlier stages will be presented 2020 Gastrointestinal Cancers Symposium, taking place January 23-25 in San Francisco, California.
“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. 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,” said lead investigator Brian M. Wolpin, MD, MPH, who is Director of the Gastrointestinal Cancer Center and Director of the Hale Family Center for Pancreatic Cancer Research at Dana-Farber Cancer Institute in Boston.
In general, GI cancers are difficult to identify early. The GI organs are deep inside the body, so small tumors can’t easily be seen or felt during routine physical exams. No screening tests are available for cancers like gallbladder, bile duct, and pancreatic cancer. Screening exams do exist for other types of GI cancers, such as colorectal and stomach cancer, but many of these tests are invasive. When GI cancers are diagnosed, they are often at advanced stages that are more difficult to treat. An accurate test based on a simple blood sample could lead to earlier diagnosis for GI cancers.
About the Study
The test to be presented at the ASCO Gastrointestinal Cancers Symposium uses cell-free DNA — degraded DNA fragments circulating through the bloodstream, which can come from a number of sources, including tumor cells that have died and released DNA fragments.
This test is based on DNA methylation — a chemical process that can change how a gene’s function is carried out by the body without changing the order of the DNA bases. Methylation plays a role in many processes in the body, including the development of cancer. The researchers use a technique called bisulfite sequencing, which allows them to identify a pattern of methylation, or signature, in the cell-free DNA. For this presented abstract, the researchers will provide data from patients with GI cancer and individuals without known cancer (non-cancer controls).
In the Circulating Cell-free Genome Atlas (CCGA) study, the researchers included patients with more than 20 tumor types at all disease stages. and non-cancer controls. In the second substudy of CCGA, plasma DNA underwent targeted methylation analysis to develop an algorithm that could identify the whether the patient had cancer and the tissue of origin of the cancer — the presence or absence of cancer and its location in the body, including cancers of the esophagus/stomach (n=67), pancreas/gallbladder/extrahepatic bile duct (n=95), liver/intrahepatic bile duct (n=29), and colon/rectum (n=121). Data included training and validation sets.
The technology had an overall sensitivity of 82% for cancer detection for the training set and 81% for the validation set, with a specificity of more than 99%. Overall accuracy for defining the GI tissue of origin among the samples for which tissue of origin was assigned was 91% and 89% for the training and validation sets.
“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. If further validated with additional testing, this approach has the potential to allow us to diagnose gastrointestinal cancers earlier, when they’re more treatable,” said Wolpin.
The test’s developers are also conducting two large population-based studies to further validate the screening potential of the test. The STRIVE study has enrolled nearly 100,000 women undergoing screening mammograms, and the SUMMIT study is enrolling 50,000 men and women without a known cancer diagnosis.
The study was funded by GRAIL, Inc.
2020 Gastrointestinal Cancers Symposium News Planning Team
Muhammad Shaalan Beg, MD, A. William Blackstock, MD, FASCO, and Richard L. Schilsky*, MD, FACP, FSCT, FASCO, American Society of Clinical Oncology (ASCO); Theodore S. Hong, MD, American Society for Radiation Oncology (ASTRO); Vance Sohn, MD, FACS, Society of Surgical Oncology (SSO).
View the disclosures for the News Planning Team: https://www.asco.org/sites/new-www.asco.org/files/content-files/about-asco/pdf/2020-GI-News-Planning-Team-Disclosures.pdf
*Dr. Schilsky’s research disclosure represents funding to ASCO for the Targeted Agent and Profiling Utilization Registry (TAPUR) clinical trial and includes the dollar value of the study drugs being provided free to patients enrolled in the trial.
ATTRIBUTION TO THE 2020 GASTROINTESTINAL CANCERS SYMPOSIUM IS REQUESTED IN ALL NEWS COVERAGE.
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About the American Gastroenterological Association Institute:
The American Gastroenterological Association (AGA) is the trusted voice of the GI community. Founded in 1897, the AGA has grown to include more than 16,000 members from around the globe who are involved in all aspects of the science, practice and advancement of gastroenterology. The AGA, a 501(c6) organization, administers all membership and public policy activities, while the AGA Institute, a 501(c3) organization, runs the organization's practice, research and educational programs. On a monthly basis, the AGA Institute publishes three highly respected journals, Gastroenterology and Clinical Gastroenterology and Hepatology, and Cellular and Molecular Gastroenterology and Hepatology. The organization's annual meeting is Digestive Disease Week®, which is held each May and is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy, and gastrointestinal surgery. The AGA Research Foundation provides digestive disease research grants on behalf of the AGA Institute.
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The American Society for Radiation Oncology (ASTRO) is the premier radiation oncology society in the world, with more than 10,000 members who are physicians, nurses, biologists, physicists, radiation therapists, dosimetrists and other health care professionals that specialize in treating patients with radiation therapies. As the leading organization in radiation oncology, the Society is dedicated to improving patient care through professional education and training live activities as well as online through the ASTRO Academy , support for clinical practice and health policy standards, advancement of science and research, and advocacy. ASTRO publishes three medical journals, International Journal of Radiation Oncology, Biology, Physics, Practical Radiation Oncology, and Advances in Radiation Oncology, developed and maintains an extensive patient website; and created the Radiation Oncology Institute, a non-profit foundation to support research and education efforts around the world that enhance and confirm the critical role of radiation therapy in improving cancer treatment. Learn more about ASTRO.
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The Society of Surgical Oncology (SSO) is a dynamic global community of cancer surgeons shaping advancements in the profession to deliver the highest quality surgical care for cancer patients. SSO promotes leading-edge research, quality standards and knowledge exchange connecting cancer surgeons worldwide to continuously improve cancer outcomes. Our highly regarded educational resources, the Society's clinical journal, Annals of Surgical Oncology and events, including SSO 2020 - International Conferenc eon Surgical Cancer Care, inspire members and spur each cancer surgeon to grow, improve and thrive. Learn more about the Society of Surgical Oncology.
Founded in 1964, the American Society of Clinical Oncology, Inc. (ASCO®) is committed to making a world of difference in cancer care. As the world’s leading organization of its kind, ASCO represents nearly 45,000 oncology professionals who care for people living with cancer. Through research, education, and promotion of the highest-quality patient care, ASCO works to conquer cancer and create a world where cancer is prevented or cured, and every survivor is healthy. ASCO is supported by its affiliate organization, the Conquer Cancer Foundation. Learn more at www.ASCO.org, explore patient education resources at www.Cancer.Net, and follow us on Facebook, Twitter, LinkedIn, and YouTube.