We may have a way to detect early cancer with one blood test. The Galleri Test is now available with an order from your doctor and it can identify more than 50 cancer types in asymptomatic adults 50 years or older. It uses AI (Artificial Intelligence) analysis of cell-free DNA to recognize pattens associated with cancer and identify the likely tissue or origin.
Remember, we only have screening tools for a few cancer types now. We can screen for cervical, lung (in heavy smokers),prostate, colon and breast cancer but that leaves over 70% of all cancers without early detection screening. The Galleri test may be the next step in screening for early detection.
While it is not yet approved by the FDA, the early results look promising. The study that enrolled 15,254 patients showed a specificity for cancer signal detection of 99.5%. This means the test was accurate in saying someone did not have cancer with few false positives. The sensitivity in detecting the cancer tissue of origin was 51.9% and it increased with stage of cancer. There was a 73.6% sensitivity ( true positives) in the cancers that cause 2/3 of cancer deaths in the US.
Different cancers shed DNA at a different rate. The greater proportion of DNA shed, the more likely it is to be picked up by the Galleri Test. The UK is currently enrolling 140,000 National Health Service patients between 50-77 years of age to further evaluate test performance.
The Galleri test can screen for some cancers that currently have no screening options and account for 70% of cancer deaths. The diagnosis of cancer through Galleri testing has the potential to improve patient survival, but this has not yet been demonstrated. .
Heres the bottom line. The test costs $949 and is not covered by insurance. It is not a one-and-done diagnostic tool and does not replace the screening that we have now. For many types of cancer there is no effective treatment even if diagnosed early. When a cancer signal is detected, the likelihood that the individual has cancer is elevated, but further investigation would be needed to make a diagnosis and treatment plan. If a patient has symptoms, a negative test would not eliminate the need for further testing for cancer. Some indolent cancers may be detected and not need treatment at all, leading to overdiagnosis and unnecessary treatment.
So the Galleri test should be considered another screening tool to accompany the ones we have now for breast, prostate, lung, cervical and colon cancer and the potential to detect 50 other types is remarkable. The out of pocket cost will be a deterrent for most people unless it is covered by insurance and more studies are needed to demonstrate accuracy, clinical utility and most of all...improved patient outcomes.