Multicancer blood test shows efficacy for early cancer detection
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A novel multicancer early detection blood test identified a common signal for more than 50 cancer types and predicted where the signal originated in the body among individuals with undiagnosed cancer.
The findings, presented at ESMO Congress, additionally showed the multicancer early detection test (MCED, GRAIL) had an excellent specificity rate for those who did not have cancer, researchers noted.
"This study shows that it is, indeed, feasible to detect cancers early using blood tests,” Deb Schrag, MD, MPH, chair of the department of medicine at Memorial Sloan Kettering Cancer Center, said during the presentation.
Methodology
The prospective PATHFINDER study included 6,621 participants aged 50 years and older (median age, 63.4 years; 63% women; 92% white) with or without additional cancer risk factors.
Researchers sought to evaluate a novel blood-based MCED test that uses cell-free DNA and machine learning to detect a common cancer signal for more than 50 cancer types, as well as predict the origin of the cancer signal. They pooled blood samples, analyzed cell-free DNA and confirmed cancer status at 1 year for all study participants.
The extent of diagnostic testing required for resolution after cancer signal detected by the MCED test served as the primary outcome. Test performance and safety served as secondary outcomes.
Key findings
Researchers reported that the test detected a cancer signal in 1.4% of individuals not previously known to have cancer and 38% of those with a positive test result had a confirmed cancer diagnosis. A GRAIL press release published the day of the presentation at ESMO stated that a refined version of the test demonstrated a positive predictive value of 43.1%. In addition, the refined test had a specificity of 99.5% compared with 99.1% with the earlier version, and both versions had a false-positive rate of less than 1%, the press release stated.
It took a median 79 days to achieve diagnostic resolution among those with a positive test result, and diagnostic resolution was achieved within 3 months among 73% of individuals.
The test identified a determinate predicted origin of the cancer in all but one of the 35 participants with a true positive result, and in 33 of these (97.1%) it correctly identified the tumor type of origin. Of note, 26 of the cancers diagnosed after a true positive result lacked standard screening.
“The results are an important first step for early cancer detection tests because they showed a good detection rate for people who had cancer and an excellent specificity rate for those who did not have cancer,” Schrag said in a press release. “In people with a positive test, it took less than 2 months to confirm the diagnosis if they had cancer and it took a bit longer if they did not have cancer, primarily because physicians opted to perform imaging studies and then repeat them a second time several months later to investigate the possibility of a cancer diagnosis.”
Schrag said few of those who received a false-positive result needed to undergo multiple invasive procedures such as biopsies and endoscopies. “This finding should help to allay concerns that these tests could cause harm by generating unnecessary procedures in people who are well,” she said.
Looking ahead
Additional research is currently underway, including a clinical trial of 140,000 asymptomatic individuals in England to assess the clinical effectiveness of MCED testing on cancer outcomes, Schrag said in the release.
“[The current] study indicates that hope is on the horizon for detecting cancers that are currently unscreenable, but of course much more work is needed and, with experience and larger samples, these assays will improve,” she said. “The tests need to be refined so they are better at distinguishing tumor DNA from all the other DNA that is circulating in the blood. It is also critical to note that the purpose of cancer screening is not to decrease the incidence of cancer, but rather to decrease cancer mortality. It is premature to reach any conclusions about how MCED testing affects mortality, which was not measured in the PATHFINDER study and requires lengthy follow-up.”
References:
- A new era of early cancer detection with blood test may change cancer screening paradigms (press release). Available at: www.eurekalert.org/news-releases/963772#. Published Sept. 11, 2022. Accessed Sept. 13, 2022.
- Correcting and replacing GRAIL announces final results from the PATHFINDER multi-cancer early detection screening study at ESMO Congress 2022. Available at: www.businesswire.com/news/home/20220911005035/en/CORRECTING-and-REPLACING-GRAIL-Announces-Final-Results-From-the-PATHFINDER-Multi-Cancer-Early-Detection-Screening-Study-at-ESMO-Congress-2022. Published Sept. 11, 2022. Accessed Sept. 14, 2022.
- Schrag D, et al. Abstract 9030. Presented at: European Society for Medical Oncology Congress; Sept. 9-13, 2022; Paris.
Perspective
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Fabrice André, MD, PhD
It is a duty of professional societies like ESMO to raise awareness of the fact that within the next 5 years, we will need more doctors, surgeons and nurses — together with more diagnostic and treatment infrastructure — to care for the rising number of people who will be identified by multicancer early detection tests. We need to involve all stakeholders in deciding new pathways of care. We need to agree who will be tested and when and where tests will be carried out, and to anticipate the changes that will happen as a result of these tests; for example, in the diagnosis and treatment of people with pancreatic and other cancers that are usually diagnosed at a much later stage.
We need comparative trials across all types of cancer to find out if having an early detection test affects morbidity and mortality. We also need to know how the tests benefit patients and how to discuss the results with them. In addition, we need to know more about the small proportion of false-positive tests — MCED results that indicate cancer is present but this is not confirmed by standard diagnostic procedures. We need some of these answers before we can calculate the cost impact of introducing MCED tests in routine clinical practice.
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Schrag D, et al. Abstract 9030. Presented at: European Society for Medical Oncology Congress; Sept. 9-13, 2022; Paris.
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