We were impressed by the commentary written by Dr. Gilbert Welch in STAT News and recommend that you read it. It is entitled “Why the FDA should not approve an ineffective multi-cancer screening test.”
We wanted to add some additional information, and STAT published our Letter to the Editor in response, available here https://www.statnews.com/2026/
Our response
Kudos to Gordon Welch for explaining why the Galleri multi-cancer screening test does not merit FDA approval and would cost taxpayers billions of dollars. We agree and add that it could potentially increase delays in cancer diagnoses and possibly deaths.
Despite its name, Galleri is not an early detection test because it misses most early cancers. The company’s two studies missed 86% and 79% of stage 1 cancers and about two-thirds of stage 2 cancers. That means that most of the people who have early cancers will be told that they are cancer-free. That’s not as good as a coin toss. Even the most advanced cancers were correctly detected only 60% – 63% of the time. That’s why we agree with Dr. Welch that there is no evidence that these tests save lives.
Meanwhile, many patients will be falsely reassured. If the test shows they don’t have any type of cancer, when they start to have symptoms, there will be a tendency to delay going to the doctor. They may want to put it off for just a few weeks or months — until after the holidays or a deadline at work — but those delays may last longer than planned.
That could be deadly. Will those risks outweigh the benefits, especially with extremely low early-stage detection for prostate, breast, ovarian, skin, and inadequate evidence of accuracy for many other cancers? What happened to patients who eventually learned that they did not have cancer despite a Galleri result suggesting they had cancer? Half underwent an invasive procedure such as biopsies, endoscopies, or surgery. They waited a median of 75 days before being told they didn’t have cancer. That’s a very long, anxious waiting period and is inevitable due to a lack of experts to conduct and interpret test results.
If millions of people take Galleri tests, the added demand for follow-up testing could lengthen waits for them and for people who have cancer. In the ideal world, where doctors have unlimited time to explain these test results to patients, and where patients understand the shortcomings of the tests, continue other screening, and don’t freak out if told the test indicates cancer, then the test might be promising.
But that’s not the world we live in. The tests could easily do the opposite, as people with results suggesting cancer require follow-up testing that overwhelms our healthcare system, potentially delaying diagnoses for people with cancer.
— Diana Zuckerman, Ph.D., and Akashleena Mallick, M.D., M.P.H., National Center for Health Research