The FDA Just Backed a Blood Test for 50 Cancers. I Think You Should Start at 35.
On Wednesday, a panel of outside experts advising the FDA voted in favor of approving Galleri, a single blood test that looks for more than fifty types of cancer at once. The vote on safety was unanimous. If the FDA follows its panel, and it usually does, Galleri will become the first multi-cancer screening test ever approved in this country.
I have been ordering this test for my patients for a while now, and I have looked closely at every competitor that has come along. Galleri is still at the top. But the panel's recommendation comes with one line I disagree with: it is meant for adults fifty and older.
What Galleri Does
Tumors shed fragments of their DNA into your bloodstream. Cancer DNA carries a distinctive pattern of chemical tags, called methylation, that is different from the DNA of your healthy cells. Galleri reads those patterns from a routine blood draw. If it finds a cancer signal, it also tells us where in the body the signal is most likely coming from.
That second part matters more than it sounds. It is the difference between "you may have cancer somewhere" and "look at the pancreas."
Here is what we know from PATHFINDER 2, the largest study of the test in North America, which followed more than 35,000 adults with no signs of cancer:
Adding Galleri to the usual screening tests found more than six times as many cancers as the usual tests found alone.
More than half of the cancers it found were stage I or II, when treatment has the best chance of working.
About seven in ten were cancers we have no routine screening test for: pancreas, liver, stomach, esophagus, ovary, and others. These are the cancers that are usually found late, when there is little left to do.
When the test said cancer, it was right about 60 percent of the time, and it pointed to the right part of the body more than 90 percent of the time.
False alarms were rare: fewer than 4 in 1,000 people.
We screen for five cancers in this country: breast, cervix, prostate, colon, and, for smokers, lung. Everything else, we find when it causes symptoms. That is what this test
changes.
Why Galleri and Not the Others
Galleri is not the only test of its kind anymore, and I get asked about the others. Here is how they compare:
Cancerguard, from Exact Sciences, the makers of Cologuard, is the main competitor. It combines DNA methylation with protein markers and covers a similar number of cancers. Its weakness is false alarms. Its specificity is 97.4 percent, which sounds excellent until you do the math: roughly 1 in 40 healthy people will get a positive result, compared with about 1 in 250 for Galleri. also does not tell us where to look, so every positive result goes straight to a CT scan of the chest, abdomen, and pelvis, often followed by a PET scan. That is a lot of radiation and a lot of worry for someone who, most of the time, does not have cancer. And Cancerguard is only offered to people fifty and older.
Shield MCD, from Guardant Health, looks for ten types of cancer. Guardant has not yet published how well it performs, and it remains a laboratory test without FDA approval.
Galleri has the most data behind it by a wide margin, including two large trials on two continents with more than 175,000 people combined. It has the lowest false-positive rate of the group, it is the only one that tells us where to look, and it is the only one an FDA panel has voted to approve.
Cancer Is Getting Younger
Now for the part I disagree with:
Over the last two years, study after study has shown the same thing: cancer is showing up earlier in life. A study from Harvard published this year found that thirteen cancers are rising in adults under fifty in at least ten countries, and that six of them, including colorectal, pancreatic, and kidney cancer, are rising faster in younger adults than in older ones.
Colorectal cancer is now the leading cause of cancer death in Americans under fifty.
Nearly three out of four of those younger patients already have advanced disease when they are diagnosed, and they wait about 40 percent longer than older patients to get that diagnosis, because nobody, including their doctors, expects cancer at thirty-eight.
This month, researchers at Washington University published a study in Nature Medicine that gets to the reason. Using data from more than 160,000 people, they found that younger generations are aging faster on the inside than their parents did at the same age. People born in the 1990s showed measurably more biological aging than people born in the late 1960s, and the faster a person was aging biologically, the higher their risk of early-onset cancers of the lung, the digestive tract, and the uterus. The link held even after accounting for inherited cancer risk.
You know how I feel about inflammation. It is the source of all evil. Obesity, a Western diet, sitting all day, poor sleep, the plastics in our bodies: these drive the inflammation that ages you from the inside, and that is where the rise in early-onset cancer is coming from. Those exposures now start in childhood. It should not surprise anyone that the cancers they cause are arriving earlier too.
Galleri was studied mainly in people fifty and older because, until recently, that is where cancer was. The studies tell us where cancer used to be. The trend lines tell us where it is going. Galleri can be ordered for adults well under fifty at a physician's discretion, and that is my practice. I start at thirty-five.
What I Recommend
First, if you are thirty-five or older, get a Galleri test, and repeat it every year. Cancer screening is not a one-time event, and a test that was clear last year says nothing about this year.
Second, keep your regular screenings. Galleri does not replace your mammogram, your colonoscopy or Cologuard, your Pap smear, your PSA, or your lung CT if you smoked. It is an addition, not a substitute, and a negative result does not guarantee you are cancer-free. It finds the cancers the other tests were never designed to catch.
Third, if you are under forty-five and have any symptoms of colon trouble, such as blood in the stool, a change in bowel habits, or unexplained anemia, do not let anyone tell you that you are too young to have cancer. Get it looked at.
Fourth, work on the thing that is driving this in the first place. Lose the visceral fat. Move every day and lift something heavy twice a week. Sleep seven to eight hours. Eat real food. Get the plastic out of your kitchen; I have put the swaps I recommend in my Amazon storefront*. Slowing your biological clock is the best cancer prevention there is, and no blood test can do that for you.
Fifth, if you are my patient, ask about Galleri at your next visit and we will order it through the office.
The Bottom Line
For the first time, we have a single blood test that can find dozens of cancers before they cause symptoms, including the ones we have never been able to screen for, and an FDA panel has now said it should be approved. Of the tests on the market, Galleri has the strongest evidence, the fewest false alarms, and the only built-in map to where the cancer is. The panel drew the line at fifty. The data on younger adults says that line is fifteen years too late.
Have you had a Galleri test, or one of the others? I would like to hear what the experience was like. Leave a comment below.
To your good health,
The Longevity Doctor®
*As an Amazon Associate I earn from qualifying purchases made through the link above. I recommend these products on their merits, and I would recommend them without the link.
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