A New Approach to Cancer Screening
The Galleri® test is a new blood test designed to screen for over 50 different types of cancer at once. Unlike traditional screening methods that check for only one cancer—such as a mammogram for breast cancer or a colonoscopy for colon cancer—the Galleri test can detect many cancers with a single blood draw. This has been called a “liquid biopsy.” It works by looking for small pieces of DNA that cancer cells release into the bloodstream. These pieces of DNA have unique chemical changes, called methylation patterns, that help scientists determine whether cancer might be present and where in the body it may have started.
The test is best studied in and recommended for adults aged 50 and older and has more accuracy for those with certain risk factors. It is not a replacement for standard cancer screenings but may be used in addition to them. In the main published study called PATHFINDER, which involved over 6,600 participants, the Galleri test showed promising results. More than 70% of the cancers it detected were types that do not have regular screening options, such as pancreatic, liver, and ovarian cancer. The false negative rate was under 1%. When the test found a signal, it correctly identified the area of the body affected about 90% of the time. However, only 38% of positive results were confirmed to be cancer, meaning some people underwent additional testing only to learn they did not have cancer.
There are several potential benefits to the Galleri test. It may help detect cancer early, when it’s easier to treat. It can find cancers that are not routinely screened for, and it’s noninvasive as a simple blood draw. However, there are also risks. The test may produce false positives, leading to follow-up scans or procedures that turn out to be unnecessary. It may also miss cancers in their earliest stages, and most insurance plans do not yet cover it.
The Galleri test represents a promising advance in cancer screening, offering the possibility of detecting multiple types of cancer early through a simple blood draw. But like any medical test, it comes with benefits and risks and it’s not for everyone. That’s why having a trusted primary care physician is so important.
At EuDoc, patients have the time and space to discuss advanced options like the Galleri test in depth. The practice offers access to cutting-edge tools, but always takes the time for thoughtful, personalized conversations to ensure that any decision, especially around new technology, is the right one for each individual. Whether exploring cancer screening, preventive care, or chronic disease management, EuDoc is committed to helping patients make informed choices with confidence and care.
Check out the interview Dr. Qiu did a couple years ago with the Chief Medical Officer of the test’s company, Grail. https://www.youtube.com/watch?v=bfsDsAPhx4I
