Blood-Based Screening Test May Aid in Detecting GI Cancers

Simultaneous specificity (>99%) of multiple cancer types, including gastrointestinal (GI) cancers across stages at high sensitivity (82%), were observed using targeted methylation analysis of cfDNA, according to an abstract published in the Journal of Clinical Oncology.¹

Accurate (92%) localization of cancers to specific regions of the GI tract was also attained. Given this data, detection of multiple GI cancers from a single noninvasive blood test could be a practical method for detecting GI and other cancers, and might facilitate diagnostic workups, according to the researchers.

This blood-based screening test will be presented at the 2020 Gastrointestinal Cancers Symposium, being held from 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,” lead investigator Brian M. Wolpin, MD, MPH, Director of the Gastrointestinal Cancer Center and Director of the Hale Family Center for Pancreatic Cancer Research at Dana-Farber Cancer Institute, said in a press release.²

Using the Circulating Cell-free Genome Atlas (CCGA), the researchers included noncancer controls and patients with more than 20 tumor types at all stages of disease. In the second substudy of CCGA, plasma DNA went through targeted methylation analysis to cultivate an algorithm that could pinpoint whether the patient had cancer and the tissue of origin of the cancer, 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). The data included training and validation sets. 

The test 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%. The overall accuracy for defining the GI tissue of origin among the samples in which the tissue of origin was assigned was 91% and 89% for the training and validation sets, 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. If further validated with additional testing, this approach has the potential to allow us to diagnose gastrointestinal cancers earlier, when they’re more treatable,” Wolpin said. 

The developers of the technology are now conducting 2 large population-based studies to further substantiate the screening potential of the test. The STRIVE study has already enrolled almost 100,000 women undergoing screening mammograms, and the SUMMIT study is in the process of enrolling 50,000 men and women without a known diagnosis of cancer. 

According to the American Society of Clinical Oncology, no screening exams are currently available for cancers like gallbladder, bile duct, and pancreatic cancer. Screening tests do exist for other types of GI cancer, like colorectal and stomach cancer, however many of them are invasive. Moreover, when GI cancers are diagnosed, they are frequently at advanced stages that are more challenging to treat.

References:

1. Wolpin BM, Richards DA, Cohn AL, et al. Performance of a blood-based test for the detection of multiple cancer types. J Clin Oncol. NCT02889978.

2. Blood-Based Test Could Help Identify Hard-to-Detect Gastrointestinal Cancers [news release]. Alexandria, Virginia. Published January 21, 2020. asco.org/about-asco/press-center/news-releases/blood-based-test-could-help-identify-hard-detect. Accessed January 22, 2020.