By: Dr. Tammy Doukas, Chief Science Officer
Multi-cancer early detection (MCED) tests screen for early warning cancer signals that are circulating in the bloodstream. They differ from traditional cancer screening tests in three ways:
- MCED tests screen for multiple cancers at once, instead of one specific cancer.
- MCED tests screen for cancer in people with no known pre-existing cancers, instead of searching for evidence of an existing tumor or its recurrence.
- MCED tests screen for cancer signals instead of hereditary gene risk.
Although MCED tests do not have FDA approval, some are commercially available because of their laboratory designed test (LDT) designation. LDT means that a test must be designed, manufactured, and used within a single laboratory. Since MCED tests analyze each patient’s blood from a single draw that is sent to a specific lab, they fall under the LDT designation.
There are multiple different types of MCED tests in development at this time. These tests are designed to identify different types of cancer signals circulating in the blood, and to use powerful analytics to determine whether these signals equate to risk. Different types of cancer signals are:
- Changes in genetic material can provide information about mutations that have occurred in DNA or RNA messages that can lead to cancer.
- DNA methylation patterns can provide information about how genes are expressed. Overexpression or underexpression of some genes can lead to cancer.
- Protein marker levels can provide information about biological changes associated with cancer.
- Immune system molecules can provide information about antibodies that may be targeting cancer cells.
- DNA fragmentation patterns can provide information about cell death that can be implicated in cancer.
- A combination of two or more of the above signal types.
Although MCED tests can uncover some early stage cancers, they should not be used in place of regular cancer screenings. This is because there can be false positives and false negatives associated with these tests, as there are with many other different types of blood tests. A false positive can cause a great deal of stress and trigger unnecessary follow-up or invasive procedures. A false negative can lure a patient into a false sense of security, while the cancer grows undetected to later stages. Used with proper caution, in addition to routine cancer screenings, MCED tests have the ability to catch cancer early and save lives.
OneTest can detect multiple different cancers at an early stage by measuring the levels of 7 different proteins circulating in the bloodstream. One or more of these proteins is secreted by many young tumors. Each one of the 7 protein markers is established in medicine as a possible indicator of the presence of cancer.
OneTest reports their test specificity as 89%. Their test sensitivity statistics include prostate (100% sensitivity), liver (92.3% sensitivity), pancreas (89% sensitivity), colorectal (77% sensitivity), lung (75% sensitivity), bladder (64% sensitivity), and others. https://onetestforcancer.com/accuracy-reliability-scientific-support
There are a couple of other types of MCED tests on the market that are multiple times more expensive, because they use detection methods that are more complicated than measuring protein levels. These other tests look at genomic changes or DNA methylation, but they ultimately produce test results of comparable sensitivity and specificity.