A Blood Test for Early Detection of Cancer
March 18, 2019
Robert E. Schoen, MD, MPH, and Randall Brand, MD, were collaborators in a multicenter investigation led by researchers from Johns Hopkins University that evaluated the efficacy, sensitivity, and specificity of measuring circulating tumor DNA (ctDNA) and proteins in the blood for detection of cancer.
“There is a lot of research that attempts to find blood-based markers for early-stage cancer before a tumor has had the chance to grow into advanced disease. The reasons are clear. The earlier you find cancer, the better chance you have at defeating it,” says Dr. Schoen.
The study utilized a test panel called CancerSEEK. The panel is based on the concept that even the tiniest tumors are undergoing apoptosis and spilling DNA into the circulation. DNA mutations in tumors are unique, and using digital genomic techniques can be detected with exquisite sensitivity and specificity. Protein biomarkers were added to detect tumors that do not shed detectable quantities of circulating tumor DNA.
CancerSEEK was tested in a cohort of just over 1,000 patients with eight different nonmetastatic cancers — ovary, breast, lung, stomach, pancreas, esophagus, liver, and colorectum — and compared them to control subjects without cancer.
“This study showed a detection rate of about 70 percent with a range of sensitivity from 69 to 98 percent, with greater than 99 percent specificity. Using machine learning, one could predict the location of the primary tumor to one or two sites nearly 83 percent of the time,” explains Dr. Schoen.
Should this technology advance to clinical utility, we would have a blood test that could detect multiple frequently occurring cancers, many for which we currently have no screening tests, including ovarian, stomach, pancreatic, liver, and esophageal cancers.
“Our Division has a number of similar investigations with respect to biomarkers and early detection,” reports Dr. Brand. For example, our pancreatic group is looking at pancreatic cyst fluid for early detection of pancreatic cancer. “This work will undoubtedly continue as the creative and dedicated efforts of our faculty in the field make steady progress,” says Dr. Schoen.
References and Further Reading
Cohen JD, Li L, Wang Y, et al. Detection and Localization of Surgically Resectable Cancers With a Multi-Analyte Blood Test. Science. 2018; 10.1126/science.aar3247. Epub ahead of print.
