HEALTH & WELLNESS
Information, Prevention & Quality of Life
By Dr. Laura Méndez
Health Analyst
The Sun Post News
September 23, 2026
A simple blood draw capable of searching for signs of dozens of cancers before symptoms appear sounds like one of the most promising developments in modern preventive medicine.
On September 23, that possibility enters an important regulatory stage in the United States.
A panel of experts advising the U.S. Food and Drug Administration is scheduled to evaluate Galleri, a multi-cancer early detection blood test developed by GRAIL and proposed for use in adults age 50 and older.
The test searches for cancer-associated patterns in fragments of DNA circulating in the bloodstream. When it detects a suspicious signal, it also attempts to identify where in the body that signal may have originated.
The potential is significant because many cancers still have no routine screening test.
But the scientific evidence also requires caution.
Galleri does not diagnose cancer, does not detect every cancer, and a negative result does not guarantee that a person is cancer-free. It should not replace mammograms, colorectal cancer screening, cervical cancer screening, lung cancer screening or other established preventive examinations.
What Is the FDA Actually Considering?
The September 23 advisory committee meeting does not automatically mean Galleri will be approved.
FDA advisers are examining the test’s benefits, risks, limitations and clinical performance before making recommendations to the agency.
The FDA will ultimately make its own regulatory decision.
Galleri has already been commercially available in the United States under certain conditions as a laboratory-developed test ordered through healthcare providers. But the FDA review represents a much more consequential question: whether sufficient evidence supports the proposed broader screening use.
The decision could influence the future of an entirely new category of cancer screening technology.
How Can One Blood Sample Search for Many Cancers?
Normal cells and cancer cells release fragments of DNA into the bloodstream.
Galleri uses next-generation sequencing technology to search for specific patterns of DNA methylation—chemical changes in DNA that can differ between normal tissue and tissue associated with cancer.
The test does not physically find a tumor in the blood.
Instead, it identifies a molecular signal suggesting that cancer may be present and attempts to predict the tissue or organ where that signal originated.
If the result indicates that a cancer signal has been detected, additional diagnostic testing is necessary.
Depending on the suspected cancer, that could involve imaging studies, laboratory testing, endoscopy or biopsy.
A positive result therefore does not automatically mean a person has cancer.
The Promise: Finding Cancers We Do Not Routinely Screen For
Existing cancer screening programs save lives, but they cover only a portion of cancers.
Established screening strategies exist for certain cancers, including breast, colorectal, cervical and lung cancer in eligible populations.
Many cancers involving the pancreas, ovaries, liver, kidneys, esophagus and other organs, however, are not routinely screened for in average-risk people without symptoms.
That is the gap multi-cancer detection tests are attempting to address.
The American Cancer Society notes that a substantial share of cancers diagnosed each year involve types for which routine screening is not currently recommended.
Finding those cancers earlier could theoretically allow treatment while disease is still localized and potentially easier to manage.
But that leads to the most important scientific question:
Does finding these cancers earlier actually reduce deaths from cancer?
That has not yet been conclusively established for multi-cancer blood screening in the general population.
What the Data Show
Materials submitted for FDA review include data from more than 25,000 participants who were followed for 12 months.
Among them, 229 people initially received a cancer-signal-detected result using the version of the test being evaluated.
Within one year, 133 of those individuals were diagnosed with cancer.
Among nearly 24,900 participants whose initial result did not detect a cancer signal, 196 were subsequently diagnosed with cancer during the same follow-up period.
Those numbers demonstrate both the potential and the limitations of the technology.
The test can identify cancer signals that might otherwise go unnoticed.
But it can also produce positive results that are not subsequently confirmed as cancer, while some people who receive negative results can still have or develop a detectable cancer.
Understanding those limitations is essential before these tests are used broadly.
The Hardest Target: Early-Stage Cancer
Cancer screening is particularly valuable when disease is detected at a stage when treatment has a greater chance of success.
This is one of the major issues FDA advisers are examining.
The sensitivity of multi-cancer blood testing is not identical across every cancer type or every stage of disease.
More advanced tumors may release greater quantities of tumor-associated material into the bloodstream, potentially making them easier to detect.
Small, early-stage cancers may release much less.
This creates an important scientific challenge: some of the cancers physicians most want to identify at an early stage can also be among the hardest for a blood test to detect.
A Negative Result Does Not Mean “I Don’t Have Cancer”
This may be the most important message for patients.
A “No Cancer Signal Detected” result does not rule out cancer.
People who receive a negative result should continue following established cancer-screening recommendations appropriate for their age, sex, medical history and individual risk.
A woman should not skip a recommended mammogram because a multi-cancer blood test was negative.
Someone due for colorectal cancer screening should not abandon it.
And a person experiencing unexplained weight loss, unusual bleeding, a persistent lump or another concerning symptom should not use a negative blood test as a reason to delay medical evaluation.
Multi-cancer tests are being studied as an additional screening tool—not as a replacement for established methods.
What About False Positives?
The opposite problem also matters.
A blood test can indicate a possible cancer signal, only for subsequent diagnostic procedures to find no cancer.
This is known as a false-positive result.
False positives can cause significant anxiety and lead to additional testing, some of which may be expensive or invasive.
Patients could undergo imaging, endoscopic procedures or biopsies while doctors attempt to determine the source of the signal.
Therefore, the potential benefit of detecting additional cancers must be balanced against the potential harm caused by unnecessary investigations.
For regulators, the question is not simply whether the test can detect cancer signals.
It is whether the overall benefits outweigh the risks when the test is used among large numbers of otherwise healthy people.
The Biggest Unanswered Question: Does It Save Lives?
This is ultimately the central issue.
Detecting more cancers is not necessarily the same as demonstrating that screening reduces cancer mortality.
To establish that a screening strategy saves lives, researchers ideally need long-term studies comparing people who receive the test with those receiving standard care and determining whether fewer people ultimately die from cancer.
That evidence takes years to develop.
Important questions therefore remain:
Who should receive multi-cancer screening?
How often should testing be repeated?
Which cancers does it detect most effectively?
What diagnostic process should follow a positive result?
How can unnecessary procedures be minimized?
And does widespread screening ultimately reduce cancer deaths?
These uncertainties do not mean the technology has no value.
They mean researchers and regulators are still determining how, when and for whom it should be used.
What This Could Mean for Florida
Florida has one of the nation’s largest populations of older adults.
That makes advances in cancer detection particularly relevant to the state.
If Galleri ultimately receives FDA approval for the proposed population of adults age 50 and older, millions of Florida residents could potentially fall within the eligible age range.
For Florida’s Hispanic community, another issue deserves attention: access.
A blood test may appear simpler than undergoing several different screening procedures.
But convenience alone does not eliminate disparities in healthcare.
Patients still need access to physicians, diagnostic imaging, specialists and potentially biopsies after a suspicious result.
Cost and insurance coverage are also important considerations.
If a screening test identifies a possible cancer but a patient cannot obtain timely diagnostic follow-up, the promise of early detection becomes much less meaningful.
Do Not Abandon Screening Methods That Already Work
Regardless of the FDA’s eventual decision on Galleri, established cancer-screening recommendations remain in place.
Patients should continue discussing mammograms, colorectal cancer screening, cervical cancer screening, lung cancer screening for eligible individuals and other appropriate preventive care with their healthcare professionals.
A new technology can sometimes create a false sense of security.
One broad blood test is not automatically superior to every cancer-specific screening method.
Different screening tools have different strengths, limitations and levels of scientific evidence.
The safest approach is to view multi-cancer blood testing as a potential addition to preventive medicine rather than a replacement for proven screening programs.
A New Frontier in Cancer Prevention
For decades, researchers have pursued the possibility of detecting multiple cancers through a simple blood sample.
Medicine is moving closer to that goal.
But there is an important difference between a promising innovation and a fully established public-health screening tool: evidence.
Galleri and similar technologies could eventually provide physicians with a new way to find cancers that currently remain hidden until later stages.
They could also generate false positives, missed cancers, additional diagnostic procedures and difficult questions about cost and access.
The scientific challenge is therefore larger than determining whether a blood test can identify molecular signals associated with cancer.
It is determining whether using that test in millions of healthy people produces more benefit than harm—and ultimately whether it helps people live longer and healthier lives.
For now, the message for patients is cautiously hopeful:
The possibility of screening for many cancers with a single blood sample is moving closer to mainstream medicine, but it has not replaced the cancer-screening tests already proven to save lives.
