A new kind of cancer test uses a blood sample to check for more than 50 types of cancer. It may help find cancer, even some types for which there is currently no test, earlier. This could save lives.
Technology is enabling astounding advances in health care, and this month Senior Spirit is sharing news about a groundbreaking way to test for cancer. Multi-cancer early detection (MCED) tests work with a single sample of blood. The test searches for specific pieces of DNA or proteins shed by cancer cells.
There is currently one such test, Galleri by GRAIL, that is available now with a doctor’s prescription. The company recommends the test for those who are at higher risk of cancer, such as folks over the age of 50.
Currently in the US, we have screening tests for five cancers:
- Mammograms check for breast cancer.
- HPV and PAP tests are used to screen for cervical cancer.
- Colonoscopies check for colorectal cancer.
- Prostate-specific antigen (PSA) tests check for prostate cancer.
- Low-dose CT scans check for signs of lung cancer.
But what about other cancers, such as pancreatic or ovarian?
“Currently, we don’t detect the majority of cancers, including highly lethal ones, such as pancreatic or ovarian cancer, until symptoms are present,” says Dr. Klein, Emeritus Chair of the Glickman Urological Kidney Institute. “But Galleri can find those cancers at a time when they’re in an earlier stage and before symptoms appear.”
Galleri also checks for certain rare cancers for which there is currently no test. These include ampullary cancer and certain kinds of soft tissue sarcoma. Galleri also tests for:
- Anal cancer
- Breast cancer
- Cervical cancer
- Esophageal cancer
- Kidney cancer
- Leukemia
- Liver cancer
- Mesothelioma
- Oral cancer
- Pancreatic cancer
- Stomach cancer
Using Next Generation DNA Sequencing and machine learning, MCED tests can use a biological process known as methylation to look for patterns in your DNA to both identify likely cancer and find where it originates.
“It’s like fingerprints and how fingerprints tell the difference between two people,” explains Dr. Klein. “The methylation patterns are fingerprints that are characteristic of each kind of cancer. They look one way for lung cancer and different for colon cancer.”
Galleri Test Accuracy
A 2021 validation study reported that the Galleri test had a false positive rate of 0.5% (versus 10% to 40% for traditional screening) indicating extremely high accuracy for finding when someone does not show signs of cancer. In other words, a false positive is very unlikely. It correctly identified greater than half of people with cancer-related signals in their blood.
“Twelve cancers, including anal, bladder, colorectal, esophageal, head and neck, liver/bile-duct, lung, lymphoma, ovary, pancreatic, plasma-cell neoplasm and stomach cancer, account for about two-thirds of all cancer deaths in the US,” says Dr. Klein. “For these 12, Galleri finds about 40% of stage I cancers, 67% of stage II cancers, 80% of stage III cancers and 95% of stage IV cancers.”
As you can see, the ability of the Galleri test to detect cancer became greater as the cancer advanced. Overall, the Galleri test was 88.7% accurate in detecting the site of the cancer in those people with a positive test result who had cancer.
Should Everyone Use an MCED Test?
At this time, the Galleri test is intended to be used in addition to traditional screening, not as a replacement. A large clinical trial https://www.nhs-galleri.org/ of 140,000 people is currently underway in the United Kingdom. The National Cancer Institute has a pilot study on the horizon. Researchers want to find definitive answers to these questions:
- How good are MCED tests at detecting cancer?
- If MCED tests are accurate at finding specific cancer, how much earlier can they find it compared to when it would be found after symptoms start?
- If MCED tests find cancers earlier, do people have better outcomes compared to people whose cancers were found after symptoms developed? In particular, does this test save lives, and, if so, by how much?
- What about false-positive results from MCED tests?
- What about false-negative results from MCED tests?
- Who should be tested?
- How often should the test be done?
The good news is, your doctor can order a Galleri test for you right now. Check with him or her to see if that may be a good idea for you. On the downside, most insurance, including Medicare, does not cover the nearly $1,000 test. However, select individual employers may pay for all or a portion of the cost.
One day, we may look for all cancers by using a blood sample alone. In the meantime, it’s important to keep abreast of new developments.
Sources:
https://www.cancer.org/cancer/screening/multi-cancer-early-detection-tests.html
https://health.clevelandclinic.org/the-galleri-test
https://www.healthline.com/health/cancer/galleri-cancer-test
https://grail.com/galleri-test/
Blog posting provided by Society of Certified Senior Advisors
