Multi-cancer early detection (MCED) tests have the potential to find more than one type of cancer from a single sample of blood. The blood sample is tested for certain pieces of DNA or proteins from cancer cells. If these are found, it might mean that the person has cancer, and it might also show which organ the cancer started in. Some MCED tests only test for the likelihood that there is cancer somewhere in the body, so if a person has a positive test result, they will need other tests, like imaging tests, to try to figure out where in the body the abnormal DNA or proteins came from.
Different MCED tests are being developed, and some (such as the GRAIL Galleri test) are available now by prescription through a doctor.
MCED tests might be very useful, if they’re proven to help prevent cancer deaths.
Currently, we have proven screening tests for some types of cancer (including breast, cervical, colorectal, prostate, and lung), because they’ve led to finding and treating these types of cancer earlier. Cancers that are found early are often easier to treat and tend to have better outcomes.
But most cancers do not have proven early detection screening tests. In fact, about 70% of all cancer deaths come from cancers for which there are currently no proven screening tests. These cancers are often diagnosed at an advanced stage, when they can be harder to treat.
MCED tests might be able to find a wide range of cancers earlier, hopefully before a person has any symptoms.
There are many companies developing and studying MCED tests, but these tests are not yet FDA cleared or approved. However, some of these tests fall under the Clinical Laboratory Improvement Act (CLIA) regulations as lab-developed tests, which still allows them to be used if ordered by a doctor. Many of the companies developing these tests are gathering data and hope eventually to get FDA approval.
At this time, much more needs to be learned before these types of tests can be recommended for widespread use in people without any symptoms of cancer.
Most of the makers of these tests claim that they are not meant to replace screening tests currently in use (such as mammograms for breast cancer, Pap tests and HPV tests for cervical cancer, stool tests and colonoscopy for colorectal cancer, the PSA blood test for prostate cancer, and low-dose CT scans for lung cancer). Instead, MCED tests might supplement current screening tests, as well as help find other cancers for which there are no proven screening tests.
Here are some of the questions about MCED tests that still need to be answered:
Research: We fund and conduct research to support advancing this science because we believe that if these tests are successful, they could save many lives that would otherwise be lost. ACS researchers have also worked with developers of some of these tests to provide advice and, in some instances, to allow them to measure the accuracy of their tests within our population studies (through research collaborations).
Advocacy: If an MCED test is proven to contribute to better outcomes among people with cancer and it gets FDA approval, we will work to make sure that everyone for whom the test is recommended has access to this test.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Liu MC. Transforming the landscape of early cancer detection using blood tests: Commentary on current methodologies and future projects. British Journal of Cancer. 2021;124:1475-1477. Accessed at https://www.nature.com/articles/s41416-020-01223-7 on June 30, 2022.
NHS-Galleri Trial Clinical. Accessed at https://grail.com/clinical-studies/nhs-galleri-trial-clinical/ on June 30, 2022.
Last Revised: June 30, 2022
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