Are Multi-Cancer Blood Tests Ready for Prime Time? --- None of the early-detection screenings are FDA approved, leading some doctors to urge caution

“A blood test that can tell if you have cancer?

 

A flurry of such tests that look for multiple cancers with a prick are in various stages of development. The one that is furthest along, Galleri, was recently the subject of a provocative Super Bowl ad from the Hims & Hers telehealth company, beaming an experimental technology into millions of households.

 

But just a few weeks later the test's manufacturer, Grail, announced disappointing study results: The test didn't reach statistical significance in later-stage cancers -- stages 3 and 4.

 

The news comes on the heels of a new law that authorizes Medicare to pay for such tests beginning in 2028 if they are approved by the U.S. Food and Drug Administration.

 

There has long been a push for better cancer screening tests. There are currently only five available, and they screen for single cancers: breast, prostate, lung, colorectal and cervical.

 

"New technologies are needed," says Dr. William Dahut, chief scientific officer of the American Cancer Society. "To come up with a way to screen for every single body part, that would mean all we would do would be doing screening tests every day."

 

But are multi-cancer blood tests ready for prime time?

 

The central question isn't whether the tests can detect cancer, but whether they can find cancers early enough to reduce deaths.

 

Despite being on the market, none of the so-called multi-cancer, early-detection tests are currently FDA approved. Rather, some -- like Grail's Galleri -- are available as laboratory-developed tests if ordered by a healthcare provider.

 

Still, you can get one. Grail says it has sold more than 475,000 Galleri tests since the product launched in 2021. The list price is $949, but many providers have discounts, says Dr. Josh Ofman, president of the company.

 

The company submitted an application to the FDA in January for use of the tests in adults with an elevated risk of cancer. That includes adults over the age of 50 and younger people with additional risk factors.

 

Ofman says that while the study didn't reduce combined stage-3 and stage-4 cancers compared with the control group, it did show a 20% reduction in stage-4 cancers.

 

The results, which haven't been published yet, are highly anticipated. They are the first randomized controlled trial of the test, which followed more than 140,000 healthy people in England's National Health Service over three years.

 

Some doctors and researchers say the preliminary data from the trial, announced in a Grail press release, isn't promising.

 

Dr. Scott Ramsey, director of the Hutchinson Institute for Cancer Outcomes Research at Fred Hutchinson Cancer Center in Seattle, says the study essentially failed to meet its goal of shifting cancer to an early stage disease by 30%.

 

"It did a poor job of picking up early stage cancers," he says. Grail's "own evidence shows that the cancers that are picked up tend to be more aggressive than the ones that are missed."

 

Grail says there was a substantial increase in the number of stage-1 and 2 cancers detected in the NHS trial, but it didn't say if the increase reached statistical significance.

 

In general, the Grail test's detection of early stage cancer in its previous studies is low at 20% to 30%, Ramsey notes; it's 40% for cancers at any stage. "When the performance is that poor, it's missing more cancer than it's finding, particularly at an early stage," he says.

 

Others, such as Dahut, viewed the results hopefully given there was a 20% decrease in stage-4 disease.

 

The Galleri test has a pretty high positive predictive value, says Dahut. Results presented at a conference last year showed that among the 216 people who had a positive blood test, there was a 60% chance they developed cancer within a year.

 

"My sense is that these tests, if they're abnormal, they're a pretty good sign that you have cancer," says Dahut. "And oftentimes the cancers that they found were cancers that are not routinely screened for, such as head and neck cancer and gastric cancers."

 

"But a negative test does not exclude the fact that you could have cancer, you still need to do other screening tests," he says.

 

To evaluate a diagnostic test's effectiveness, it's important to look at both its sensitivity and its specificity, says Dr. Badrinath Konety, president of the Allina Health Cancer Institute in Minneapolis.

 

Sensitivity is how well a test identifies disease, while specificity is how well it avoids false positives.

 

Grail's test appears to have higher sensitivity for more uncommon cancers but less so for common ones, says Konety, particularly when it is early stage common cancers, such as breast and prostate cancer.

 

If a test is positive, people still have to go through the routine diagnostic procedures.

 

"If a test is positive this is going to lead to X-rays and biopsies and additional interventions which are not only costly but can add to complications and the suffering of patients, and what if everything turns out to be negative," Konety says.

 

The tests do a good job of finding cancer. But if someone tests negative for a cancer, Konety is worried the result may create a false sense of complacency, leading them to avoid traditional screening tests. "Are we going to give people a false sense of comfort?" he says.

 

The bottom line: No professional medical societies currently recommend multi-cancer early-detection tests. While they hold promise, their benefits remain unproven. So until the science is settled, it's best to stick with routine cancer screenings.” [2]

 

1. The Galleri test measures methylation patterns in cell-free DNA (cfDNA) circulating in the bloodstream to identify "signals" of cancer. It is designed as a multi-cancer early detection (MCED) tool that can screen for over 50 types of cancer from a single blood draw.

 

2. Your Health: Are Multi-Cancer Blood Tests Ready for Prime Time? --- None of the early-detection screenings are FDA approved, leading some doctors to urge caution. Reddy, Sumathi.  Wall Street Journal, Eastern edition; New York, N.Y.. 10 Mar 2026: A12.