Catching Cancer Early
In data presented at the annual meeting of the American Society of Clinical Oncology (ASCO), GRAIL, a Menlo, Park, California-based startup company, demonstrated impressive, though early, results for its cancer blood test. The company has raised $1.6 billion in venture capital to prove that a blood test can detect cancer in healthy people, according to an article by Matthew Herper in STAT News.
Data from a pilot study demonstrate that GRAIL’s test can detect cancer in the blood with few false positives, as well as identifying the location of the tumor in the body. The test appears to be more likely to identify deadly tumors if they are more deadly.
The Circulating Cell-free Genome Atlas (CCGA) study was designed to show that GRAIL’s technology can detect cancer at an early stage with a single blood test. Data revealed that GRAIL’s investigational multi-cancer blood test detected a strong signal for 12 deadly cancer types at early stages with a very high specificity of at least 99 percent (or a false positive rate of one percent or less). Additionally, the test identified where the cancer originated in the body (the tissue of origin) with high accuracy.
According to GRAIL. detection rates (sensitivity) for the 12 deadly cancer types ranged from 59 to 86 percent at early stages (stages I-III). A combined analysis of this group of cancers showed robust detection at early stages (34 percent, 77 percent, and 84 percent at stages I, II, and III, respectively). In addition, a tissue of origin result was provided for 94 percent of all cancers detected. Of these, the test accurately identified the tissue of origin in 90 percent of cases. Cancer types were anorectal, colorectal, esophageal, gastric, head and neck, hormone receptor negative breast, liver, lung, ovarian, and pancreatic cancers, as well as multiple myeloma and lymphoid neoplasms. Collectively, these cancer types account for about 63 percent of all U.S. cancer deaths.
As Jennifer Cook, chief executive officer at GRAIL, explained, “These exciting results suggest we can achieve what we believe are the requirements for a cancer screening blood test, including detection of multiple deadly cancer types at early stages in a single test, high accuracy in determining where the cancer originated and a very low false positive rate. Our improved methylation-based technology has the potential to address gaps that exist with today’s screening options, which are limited to a few cancer types and only screen for one cancer type at a time. Based on these positive data, we plan to advance development of our test toward commercialization.”
Minetta Liu, MD, research chair and professor, Department of Oncology, Mayo Clinic, who presented one of the ASCO papers, added, “These very promising data indicate that a highly specific blood test for early cancer detection is approaching reality. The exceptional accuracy in determining the tissue of origin across all stages for those malignancies with significant cancer-specific mortality suggests that, if a cancer is detected, the test will inform where the tumor originated in the majority of cases. This factor is critical to streamline the clinical workup.”
Results are reported at 99 percent specificity, meaning that the false positive rate is 1 percent or less. Cancer incidence rates indicate that some of the people enrolled in the non-cancer group may have had an undiagnosed cancer at enrollment. Follow-up of participants in CCGA is ongoing, and outcomes will be collected for five years.
