Almost all of us know someone in our lives who have heard the words, “I’m sorry, you have cancer.” As a physician, I’ve said those words to patients far too often. The most difficult discussions are when we have discovered cancer too late to treat it well. We have improved our ability to catch cancer with screening tests for lung, colon, prostate, cervical, and breast cancer. Unfortunately, most cancer deaths occur from cancers that do not have screening tests. Galleri aims to close that gap.
What is Galleri?
Galleri is a blood test that looks for signals that come from different types of cancer. It is in a group of tests called multi-cancer early detection tests. Cancer can shed small pieces of DNA into the blood. Galleri searches for the chemical “tag” (called methylation) on that DNA to look for a cancer signal. If a signal is found, the test can often predict where in the body the cancer may be coming from. The test is designed to be repeated yearly.
Who is a good candidate for the test?
Cancer risk rises with age. Because cancer risk increases with age, the Galleri test is recommended at age 50 and older. If you have a strong family history of cancer, make sure you discuss this with your physician. You may be a candidate for Galleri sooner or additional supplemental cancer screenings.
Who should not take the Galleri test?
You should not take the Galleri test if:
- You have received a cancer diagnosis or treatment for cancer in the last 3 years
- You are pregnant
- You are under the age of 22
Does Galleri replace current recommended cancer screenings?
No. Galleri is meant to be used in addition to standard cancer screening guidelines. You need to keep up with your cancer screenings for colon, lung, breast, cervical, and prostate cancer.
What is the possible added value of a Galleri test?
Galleri can look for cancers that we do not have screening tests for including:
- Pancreatic cancer
- Liver/bile duct cancer
- Ovarian cancer
These cancers are usually found late, so detecting them early is where the test has the most potential benefit.
What are some potential problems with the Galleri test?
- It has not yet been proven to help people live longer
- Detection currently is still the weakest at the most curable stages of cancer
- It has yet to be FDA approved. It recently was endorsed by the FDA advisory panel and may be approved in the future
What happens if I get a positive test?
A positive test does not mean you have cancer, but further testing will be needed. Galleri points to the correct location of the cancer 9 out of 10 times, giving your physician direction on what to do next. Further testing may include:
- Imaging such as CT scans or MRIs
- Consultation with an oncologist (cancer doctor)
- Rarely biopsies or invasive procedures
If cancer is identified on the additional testing, you will get appropriate treatment. If cancer is not identified, your physician will discuss and arrange appropriate surveillance of the positive result.
What happens if I get a negative test?
A negative result is reassuring but does not guarantee that you do not have cancer. The test tells us with 99.6% specificity that you are cancer free. This means that 99.6% of people who took the test and received a negative test did not have cancer. If you have symptoms that are concerning you such as unexplained swollen glands, unexplained weight loss, unexplained night sweats or fevers you still need to reach out to your physician.
Bottom Line
Galleri is a promising blood test that may add information about your cancer risk, especially for those cancers that have no other screenings. It will not replace your current screenings but can be an additional, powerful tool to help optimize your health. Be sure to discuss if the Galleri test is right for you at your annual visit or upcoming appointment with your physician.
