The company’s ongoing Circulating Cell-free Genome Atlas study spans more than 15,000 participants, including those with and without cancer diagnoses. Results presented last year showed the blood test could detect 12 different early-stage cancers—which together account for nearly two-thirds of all cancer deaths in the U.S.—before they had a chance to spread to the rest of the body.
In the latest substudy of about 6,700 people, the test was able to specify the organ where the cancer was growing with 93% accuracy and delivered an overall false-positive rate of less than 1% using a single drawn blood sample. The results were published in the Annals of Oncology.
“At Grail, we believe that multi-cancer early detection has the potential to significantly reduce cancer mortality,” said co-founder Alex Aravanis, who serves as chief scientific officer and head of R&D. “We believe this is a seminal moment in the field of cancer detection.”
RELATED: In early study results, Grail's blood test identifies 12 cancers before they spread
The majority of deadly cancers do not have recommended early screening tests, according to the company, resulting in tumors being detected too late for many therapies to be effective.
The substudy’s overall detection rate for all cancer types was 43.9% across stages I, II and III, when the disease is still localized and has yet to spread and metastasize throughout the body.
Among the 12 prespecified cancers, that overall detection rate rose to 67.3%—including cancers of the anus, bladder, colon and rectum, esophagus, head and neck, liver and bile-duct, lungs, lymphoma, ovaries, pancreas and stomach, as well as plasma cell neoplasms such as multiple myeloma.
That rate is a slight drop from the 76% those dozen cancers demonstrated at 2019’s annual meeting of the American Society of Clinical Oncology in an analysis of almost 900 samples. The test did become more effective as the cancer progressed, detecting 39% in stage I, 69% in stage II, 83% in stage III and 92% in stage IV.
“The promising results from this independent validation data set demonstrate the robustness of the test performance, including its ability to detect multiple cancer types, and its generalizability to broader populations due to a low false positive rate,” said the study’s co-lead author, Minetta Liu, research chair and professor in the department of oncology at the Mayo Clinic.
“In addition, the high accuracy in identifying the anatomic origin of the primary cancer, in conjunction with detection of a positive cancer signal in the blood, will allow providers to efficiently direct next steps for each individual’s diagnostic work-up and subsequent clinical care,” said Liu.
RELATED: Using water and gold, Australian researchers discover 'universal cancer biomarker'
The test employs next-generation sequencing to analyze clusters of methyl chemical groups attached to the DNA of cancer cells, which help regulate their activity within cells. Found floating in the bloodstream, these methylation patterns differ remarkably from DNA derived from healthy cells and can provide information about where in the body the cancer began.
“Our previous work indicated that methylation-based tests outperform traditional DNA-sequencing approaches to detecting multiple forms of cancer in blood samples,” said co-lead author Geoffrey Oxnard, a medical oncologist at the Dana-Farber Cancer Institute. “The results of this study suggest that such assays could be a feasible way of screening people for a wide variety of cancers.”