Researchers say the new results of the Garelli blood test, an assay that can detect up to 50 types of cancer, suggest that it may be a useful aid to standard screening. ..
This study has not been approved by the U.S. Food and Drug Administration, but it has been. Commercially available In the United States, the Providence Health System costs about $ 950 out-of-pocket. It is used in pilot trials conducted by the United Kingdom National Health Service in the United Kingdom.
The new results are from the Circulating Cell-free Genome Atlas (CCGA) study. Release To Annual Tumor Report..
The Galleri test, being developed by Grail, uses next-generation sequencing to analyze the placement of methyl groups on circulating cell-free DNA in blood samples.
The new results show that there were few false-positive results (0.5%) because the specificity of cancer signal detection was 99.5%.
However, the overall sensitivity of the test for any stage of the cancer was only 51.5%, but much higher for late-stage cancer (for example, 90.1% for stage IV cancer).
Cancer signals were detected in more than 50 types of cancer, and the overall accuracy of predicting the origin of cancer signals in true positive results was 88.7%.
“This study is a validation of previous findings and improvements in the assay, a new paradigm for screening individuals for multiple cancers with a single blood test, as opposed to the current situation of screening individual cancers. We will set the stage. ” Lead author Eric Klein, MD, Chairman of the Glickman Urology and Kidney Institute at the Cleveland Clinic, Ohio.
He said Medscape Medical News This test supplements and does not replace standard screening tests such as: Colonoscopy Or Mammography.. “It is initially most useful for patients at high risk of cancer and is recommended for use in adults at high risk of cancer, such as those over the age of 50,” Klein said.
However, experts not involved in the study questioned whether the test was sufficiently sensitive.
Dr. Daniel Stover, MD-Arthur G. James Cancer Hospital and Richard J. Sorab Institute (Columbus, Ohio), a medical oncologist at The Ohio State University Cancer Center, have pros and cons to consider in this test. I pointed out that there is.
“The advantage is that this is a single minimally invasive blood test for the potential detection of many different types of cancer,” he said. Medscape Medical News..
“But the sensitivity is not perfect. Over 50% of the confirmed cancers were detected by this test, and most of the sensitivities were better for higher stage cancers,” he said.
Final result
The latest findings are the third and final results from the CCGA study.
The study cohort included 4077 individuals, of whom 2823 were diagnosed with cancer and 1254 were cancer-free. The average age of the cohort was 60.6 years. 54.9% (1552/2823) of cancer patients had stage I / II disease.
The overall sensitivity was only 51.5%, but the sensitivity of cancer signal detection was significantly improved in late-stage cancers. Sensitivity was 90.1% for stage IV, 77.0% for stage III, 40.4% for stage II, and 16.8% for stage I cancer.
Sensitivity also includes pre-designated groups of 12 cancer classes (anus, bladder, intestine, esophagus, stomach, head and neck, liver and bile ducts, lungs, ovaries, which account for two-thirds of cancer deaths in the United States each year. And pancreatic cancer, and Lymphoma And multiple myeloma). The overall sensitivity of these cancers was 76.3% at all stages and 67.6% at stages I-III.
To better understand how testing is performed in potential screening populations, the authors have positive predictions (PPV) for SEER cancer incidence and staging in patients aged 50-79 years. ) And the negative predicted value (NPV) were estimated. The PPV for cancer signal detection was 44.4% and the NPV was 99.4%.
“The planned studies are BRCA and Lynch Syndrome, And detect minimal residual lesions after treatment of known cancers, monitor treatment response, and use it as an early indicator of recurrence, “said Klein.
Waiting for data
Stover also said the test was “conceptually exciting, but before considering its widespread use, more data, especially future validation and more data within individual cancer types. I’m waiting for you. “
“If validated, this is most likely to be used as a companion test for standard screening approaches such as colonoscopy and mammography, which are already established screening methods,” Stover said. ..
He emphasized that there are two main questions regarding testing-sensitivity and cost. It is unclear whether this test is sensitive enough and how it relates to follow-up and biopsy use. “Guidance from the governing body and opinions from experts in cancer screening and health economics are important, especially for new screening tests that can affect a large number of patients,” he said.
This survey is by GRAIL, Inc. Supported by. Klein is a Grail consultant.
Ann Oncol. Published online on June 25, 2021. Full text
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