dr David Myers, an internal medicine doctor in Metairie, received the first positive result in a dozen patient blood draws last summer for a new blood test that detects cancer.
A healthy patient in her 60s had a marker that suggested she might have a cancer related to HPV or the human papillomavirus. After some detective work and a close examination of her lungs and throat, they found a two centimeter squamous cell carcinoma with stage 2 anorectal cancer. She has been treated and is now cancer free.
Had symptoms in later stages been indicative of the cancer, the results might have been less favorable. Stage 3 anorectal cancer has a 50% survival rate. At stage 4, it drops to 30%, Myers said.
“In her case, it was life-saving,” said Myers, who performed the test on about 115 patients who are members of his concierge-style practice.
Until troubling symptoms lead to a cancer diagnosis, the outlook is often bleak. That’s especially true in Louisiana, where more people die from cancer than almost anywhere else in the United States
Screenings such as mammograms, pap smears, and colonoscopies offer some diagnoses, but many in Louisiana learn of cancer late, and later diagnoses disproportionately affect blacks in the state. A variety of new tests, including the Galleri test that Myers uses, could allow faster diagnosis and earlier treatment for cancer.
With tests like this one — known as liquid biopsies — showing more promise, clinical trials are increasing in Louisiana offering the test free to participants.
What is it?
The technology for the Galleri test was born from the same type of blood tests that indicate chromosomal abnormalities such as Down syndrome and trisomy 13 and 18 in pregnant women. Like a developing fetus, cancer sheds fragments of DNA into the bloodstream.
The tiny bits of cancer DNA are wrapped in methyl groups, like an electric wire wrapped in a rubber cord. The test examines how DNA is packaged and identifies the type of cancer by comparing it to an ever-growing database of known cancer methylation patterns.
Last week, Grail, the company that makes Galleri, released results from a clinical study called the Pathfinder study, which discovered dozens of new cancer cases in around 6,600 adults over the age of 50. Almost half were detected in early stages and 71% of them The newly detected cancers were types that are not normally screened for, such as: B. Ovarian and pancreatic cancer.
In the study, 92 of the 6,621 patients tested were flagged as having potential cancer. Additional tests confirmed cancer in 35 people – about 1.4% of the original group.
Although scientists are optimistic about the tests and dozens of companies have invested in developing the tests, there are potential downsides.
The test misses two deadly cancers 100% of the time: early-stage melanoma, because the skin cancer cells shed off the body rather than in the blood, and brain tumors, Myers warned.
“It gets all the other big, bad cancers — the things that we don’t have a way of looking at that everyone’s scared of,” Myers said.
The test should also not give the all-clear for the cancer status. dr Margaret Pelitere, a New Orleans-based internal medicine physician, recommends it but still has patients do the standard screening tests.
“Statistically, I think that’s a very good thing,” said Pelitere, who had a positive test on one of her 32 tests, likely lymphoma. “But this does not replace other cancer screening tests such as colonoscopy and mammography.”
During a one-year follow-up of the 6,662 Galleri study patients, 29 cancers were identified during routine screenings that were not flagged by the test, and an additional 56 cancers were diagnosed after symptoms appeared or tumors were discovered incidentally or during surveillance for cancer recurrence .
There are also false alarms. In the most recent study, 38% of the positive results were correct. However, the false positives still made up a small portion of the overall study group. And the rate of false positives is by design, Myers said.
“These tests have the power to capture many positive results,” Myers said. “We don’t want to miss anything.”
Then there’s the cost. A test costs about $950 and is recommended annually. The insurance doesn’t cover it.
“Probably 80% of Louisiana residents can’t afford that,” said Tony Ye Hu, director of Tulane University’s Center for Cellular and Molecular Diagnostics. Hu’s work focuses on identifying biomarkers for cancer and infectious diseases, and he is also researching a liquid biopsy test to detect pancreatic cancer.
However, citing the sharp drop in the cost of COVID testing over the past two years, Hu said political will can reduce testing costs, especially if its use is widespread.
Galleri isn’t currently FDA approved, but a bipartisan bill has been introduced that would require liquid biopsy testing coverage for Medicare once it does. If costs remain the same, coverage for Louisiana’s 900,000 Medicare patients — about 20% of the state’s population — would total about $900 million.
So far there is no data showing that widespread liquid biopsy screening would reduce the risk of death.
“You have to do very large studies to show that this is beneficial to the population,” said Dr. Pedro Barata, a former Tulane University oncologist who uses liquid biopsy to determine treatment for existing cancers. Screenings such as colonoscopy and mammography are recommended in certain age groups because they have been shown to save lives.
Doctors agree that this is not an ideal test for every patient, especially if they have a poor prognosis from other diseases or are elderly. And some slow-growing cancers, like prostate cancer, hormonally sensitive breast cancer, and some thyroid cancers, don’t necessarily require aggressive treatment.
“For some people, early treatment of a disease doesn’t always bode well,” Barata said. Some cancers don’t progress to a worrying point, and in these cases the cure – painful drugs that wipe out the body’s defenses – can be worse than the disease.
Despite these concerns, most agree that blood tests will become more of a standard detection tool in the future as artificial intelligence learns the distinct patterns of different types of cancer.
“It gets even better. The test is learning,” Myers said. The anorectal cancer patient’s blood sample was added to Galleri’s database to help others with similar patterns diagnose cancer more quickly.
Further clinical studies
According to the company, a total of about 480 patients have had the Galleri test in Louisiana, although that doesn’t include people in some large studies or any of the other blood tests for cancer on the market.
Ochsner Health has partnered with Galleri and, according to Dr. Marc Matrana enrolled 1,000 patients over 50 in New Orleans and Baton Rouge in Grail’s Pathfinder 2 study, a follow-up study that will follow patients for three years , Physician Lead, Precision Cancer Therapy at Ochsner.
Ochsner is also enrolling 7,500 people in another study called the Reflection Study, which will track how the Galleri test affects the health outcomes of high-risk patients with low socioeconomic status who typically do not have good access to health care.
Of the few dozen patients at Ochsner who have so far chosen to pay for tests out of their own pocket, Matrana has had a positive result. He expects that in the future the test will only be part of a standard examination by a preventive doctor.
“Our prediction is that pretty quickly over the years, these tests will just be a part of how we practice medicine,” Matrana said.