Multi-cancer early detection tests–MCEDs for short–are being touted as game-changers with the potential to change cancer screening and detection within the next 5 to 7 years.
In our ongoing Conversations in Cancer series, Diane Reidy-Lagunes, MD, a medical oncologist at Duke Health, talks to Kevin Oeffinger, MD, founding Director of the Duke Cancer Institute's Center for Onco-Primary Care, and Co-Director of the DCI's Supportive Care and Survivorship Center. He is also the principal investigator at Duke for Pathfinder 2, a large-scale, multi-center clinical trial that has been studying how well these blood tests can detect cancers.
Learn how these tests work, the benefits and concerns, and who should get tested.
Why are these blood tests being called game-changers?
The MCEDs could be a game-changer in pancreatic cancer, liver cancer, and ovarian cancer; cancers for which there is no good screening.
Cancer screening saves lives, but today’s screening tests only detect five cancers–breast, colorectal, prostate, cervical, and lung–and they screen for one cancer at a time.
There are no recommended screening tests for nearly half of all cancers diagnosed annually, which account for about two-thirds of cancer deaths. These cancers are often found at later stages when they are harder to treat.
How do MCEDs work?
These tests use a single tube of blood to screen for up to 50 cancers. They work by detecting cancer cells floating in the blood. A positive test can identify the mutation within the DNA and the site of origin in the body.
Duke has been involved with the Galleri test through the Pathfinder clinical trials, but other companies are also developing cancer-detecting tests and using different methods to analyze the results. Single cancer early detection tests are also being studied.
How effective/accurate are they at detecting cancer?
The Pathfinder clinical trials have been following more than 42,000 participants worldwide. They measure how often the test finds cancer, whether people keep up with standard screenings, and what happens after early signs of cancer are detected.
In October 2025, researchers reported that the Galleri test helped detect more than seven times as many cancers as standard screenings alone. More than half of the cancers were found in early stages. Questions remain about whether the tests reduce cancer mortality.
What are the benefits and risks?
Benefits
- Detecting cancer early can improve survival and reduce the risk of death from cancers found.
- Blood analysis may lead to better treatment decisions that are more cost-effective and less toxic.
- Once the blood tests are covered by private insurance companies, Medicare, and Medicaid, it will be easier to get screened.
Potential Concerns
- Concerns over false positives or false negatives.
- Studies are evaluating how the test compares with common screening tests.
- We need to evaluate if we do more harm than good when looking further and the cancer is not there.
Can people get these tests now, even if they are not FDA-approved?
Doctors can write an order for the blood test that can be taken to a local lab. Some of the tests are already included in insurance plans.
Who should get tested?
These tests are not intended for people who think they have cancer or are undergoing cancer treatment.
People who may want to consider being tested are:
- 50 years old or older.
- Have a family history that indicates high risk, such as a BRCA1 or 2 mutation.
- At elevated risk due to previous cancer, lifestyle, or environmental factors, such as smoking or obesity.
Why should someone go to Duke's virtual MCED Clinic?
Duke's virtual MCED clinic brings together primary care providers, cancer prevention experts, and oncologists to provide personalized guidance on MCED testing. They provide support before, during, and after the testing process. This support includes:
- Assessment of personal and family cancer history and current screening status.
- Education about what MCED tests can and cannot detect.
- Shared decision-making regarding whether testing is appropriate.
- Coordination of testing and interpretation of results.
- Guidance on next steps based on test outcomes.
What happens after testing?
If the test is negative, recommended cancer screenings and other age-appropriate preventive care should be followed, as a negative result does not rule out cancer or replace regular cancer screenings.
If the test is positive, the MCED clinic quickly connects people with specialists who can determine the most appropriate diagnostic workup based on the cancer signal the test identified. This may include advanced imaging, laboratory testing, genetic evaluation, or referral to disease-specific oncology experts. The clinic also provides guidance and support to help reduce anxiety associated with an abnormal result.
