A blood-based screening test can accurately detect solid tumors and hematologic malignancies, even at early stages, according to study results published in Annals of Oncology.1

The multicancer early detection test, called Galleri™, was able to detect a wide range of cancers and establishes the beginnings of a new paradigm for cancer screening, according to study author Eric A. Klein, MD, chairman of the Glickman Urological & Kidney Institute at Cleveland Clinic in Ohio.

“Most cancer deaths in the United States and around the world are from cancers for which there is no screening test,” Dr Klein said. “A test like this would be useful in shifting the stage at which many cancers are diagnosed from late stage to earlier stages when they are easier to cure.”

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Dr Klein explained that the test uses cell-free DNA (cfDNA) sequencing and machine learning. It first provides a binary result: a cancer signal is detected or not detected. If a cancer signal is detected, the test then predicts where the cancer is located in the body.

GRAIL, Inc., the company that developed the test, has made it available in the United States by prescription only and to complement other, existing screening methods.2

Harnessing cfDNA

In the past, cfDNA has been harnessed to assess tumors that had already been identified, explained Michael J. Hall, MD, chair of the department of clinical genetics at Fox Chase Cancer Center in Philadelphia, Pennsylvania.

“We have used cfDNA to understand what genetic or genomic drivers are present in tumors without having to go in and cut the tumors out,” said Dr Hall, who was not involved in the study of the test. “It has also been used in certain types of cancers in a predictive fashion when we are concerned about monitoring risk for recurrence.”

The Galleri test harnesses cfDNA in a new and incredibly powerful way, Dr Hall added.

“Here, they are using it to try to screen or detect cancers that we wouldn’t otherwise know are there,” Dr Hall said. “Hopefully, it will allow us to detect them early enough to do something less invasive or morbid to the patient.”

Indeed, according to Dr Klein, the test would allow for a screening paradigm that is much different from existing cancer screening.

“We only have 5 established screening paradigms: PSA for prostate cancer, mammography for breast cancer, colonoscopy for colon cancer, Pap smears for cervical cancer, and low-dose CT for people at high risk for lung cancer,” Dr Klein said. “Currently, these tests are used to screen individuals for individual cancers. This would be a major shift to screen for multiple cancers at once.”

Study Results

Dr Klein and colleagues recently evaluated the test in a substudy of the Circulating Cell-free Genome Atlas (CCGA) study (ClinicalTrials.gov Identifier: NCT02889978).1

The researchers analyzed 4077 participants — 2823 with cancer and 1254 without cancer at 1 year of follow-up.

The test demonstrated high specificity for cancer signal detection and high accuracy for cancer origin prediction, and it detected more than 50 cancer types, the researchers found.

The specificity for cancer signal detection was 99.5%. The sensitivity was 51.5% overall but increased with increasing cancer stage — 16.8% for stage I, 40.4% for stage II, 77.0% for stage III, and 90.1% for stage IV.

Among patients with a true positive cancer detection result, the overall accuracy of cancer signal origin prediction was 88.7%.

The researchers also looked specifically at 12 cancers that account for approximately two-thirds of annual cancer deaths in the United States (anal, bladder, colorectal, esophageal, head and neck, liver/bile duct, lung, ovarian, pancreatic, stomach, lymphoma, and plasma cell neoplasms). 

The sensitivity of the test was 76.3% for the 12 cancers overall and 67.6% for stage I-III cancers.

“This test has the potential, if used as routine in patients at risk for those cancers, to find the cancers before symptoms occur and at an early enough stage when they should be curable,” Dr Klein said. “You can cure something like early-stage ovarian cancer, but you can’t cure late-stage ovarian cancer.”