Can cancer blood tests hold the promise of saving lives?

Jacob Marquez, coordinator of clinical research at the Knight Cancer Institute at Oregon Health & Science University in Portland, Oregon, draws blood from clinical study participant David Parker on March 14. Parker is one of hundreds of people participating in a trial for a new liquid biopsy technology that can detect early signs of cancer in a person’s blood. (Gillian Flaccus, Associated Press)

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CANBY, Ore. — Joyce Ares had just turned 74 and was feeling great when she agreed to donate a blood sample for research. So she was surprised when the screening test came back positive for signs of cancer.

After a new blood test, a PET scan and a needle biopsy, he was diagnosed with Hodgkin’s lymphoma.

“I cried,” said the retired real estate broker. “Just a few tears and thought, ‘OK, now what do we do?'”

The Canby, Oregon resident had volunteered to take a blood test that is being touted as a new frontier in cancer screening for healthy people. It searches for cancer by checking DNA fragments released by tumor cells.

Such blood tests, called liquid biopsies, are already used in cancer patients to tailor their treatment and check if tumors come back.

Now, a company is promoting its blood test to people with no signs of cancer to detect tumors in the pancreas, ovaries, and other sites for which no screening method is recommended.

The question remains whether such cancer blood tests — if added to routine care — could improve Americans’ health or help meet the White House’s goal of halving the death rate. by cancer over the next 25 years.

With advances in DNA sequencing and data science making blood testing possible, California-based Grail and other companies are racing to bring them to market.

And US government researchers are planning a big experiment – possibly lasting seven years and with 200,000 participants – to see if blood tests can hold the promise of catching more cancers sooner and saving lives.

Joyce Ares sits for a portrait in the dining room of her home on March 18, in Canby, Oregon.  When she turned 74, Ares felt great when she agreed to donate a blood sample for research.  So she was surprised when the screening test came back positive for signs of cancer.  After a new blood test, a PET scan and a needle biopsy, he was diagnosed with Hodgkin's lymphoma.
Joyce Ares sits for a portrait in the dining room of her home on March 18, in Canby, Oregon. When she turned 74, Ares felt great when she agreed to donate a blood sample for research. So she was surprised when the screening test came back positive for signs of cancer. After a new blood test, a PET scan and a needle biopsy, he was diagnosed with Hodgkin’s lymphoma. (Photo: Nathan Howard, Associated Press)

“They look wonderful, but we don’t have enough information,” said Dr. Lori Minasian of the National Cancer Institute, who is helping plan the research. “We don’t have definitive data that shows they will reduce the risk of dying from cancer.”

Grail is far ahead of other companies with 2,000 doctors willing to order the $949 test. Most insurance plans do not cover the cost. The tests are marketed without the endorsement of medical groups or the recommendation of US health authorities. A review by the Food and Drug Administration is not required for this type of test.

“For a drug, the FDA requires that there be a high probability that not only are the benefits proven, but that they outweigh the harms. This is not the case for devices like blood tests” , said Dr. Barry Kramer of the Lisa Schwartz Foundation. for truth in medicine.

Grail plans to seek FDA approval, but markets its test as it submits data to the agency.

The history of cancer screening has taught caution. In 2004, Japan halted mass screening of infants for childhood cancer after studies showed it was not saving lives. Last year, a 16-year study of 200,000 women in the UK found that regular screening for ovarian cancer made no difference in deaths.

Cases like these have revealed some surprises: Screening reveals some cancers that don’t need to be cured. On the other hand, many dangerous cancers grow so quickly that they escape detection and turn out to be deadly anyway.

And screening can do more harm than good: anxiety caused by false positives, unnecessary costs and serious side effects of cancer care. Prostate-specific antigen testing for men can lead to treatment complications such as incontinence or impotence, even when some slow-growing prostate cancers would never have caused problems.

Vials of blood from a participant in a clinical study of the effectiveness of a new liquid biopsy technology are packaged for shipment to Oregon Health & Science University in Portland, Oregon on March 14.  The clinical trial will follow hundreds of participants for three years.  to see if signals of cancers that participants would later develop were present in their blood.
Vials of blood from a participant in a clinical study of the effectiveness of a new liquid biopsy technology are packaged for shipment to Oregon Health & Science University in Portland, Oregon on March 14. The clinical trial will follow hundreds of participants for three years. to see if signals of cancers that participants would later develop were present in their blood. (Photo: Gillian Flaccus)

The evidence is strongest for screening tests for breast, cervical and colon cancers. For some smokers, screening for lung cancer is recommended.

Recommended tests – mammography, PAP tests, colonoscopy – look for cancer at a time. New blood tests look for multiple cancers at once. That’s a plus, according to Grail director Dr. Joshua Ofman.

“We screen for four or five cancers in this country, but (many) cancer deaths are from cancers that we don’t screen for at all,” Ofman said.

Dr. Tomasz Beer of Oregon Health & Science University in Portland led the company-sponsored study that Joyce Ares joined in 2020. After a miserable winter of chemotherapy and radiation, doctors told her that the treatment was successful.

His case isn’t an outlier, “but it’s the kind of ideal outcome hoped for, and not everyone will have that,” Beer said.

Although there were other early cancers detected among study participants, some had less clear experiences. For some, the blood tests led to scans that never located the cancer, which could mean the result was a false positive, or it could mean there is a mysterious cancer that will show up later. For others, blood tests detected cancer that turned out to be advanced and aggressive, Beer said. An older participant with a bad case refused treatment.

Grail continues to update its test as it learns from these studies and is sponsoring a trial with Britain’s National Health Service in 140,000 people to see if the blood test can reduce the number of cancers detected at an early stage. advanced.

Although Ares feels lucky, it’s impossible to know if her test added healthy years to her life or made no real difference, said Kramer, former director of the Cancer Prevention Division of the National Cancer Institute.

“I sincerely hope Joyce benefited from this test,” Kramer said when told about her experience. “But unfortunately we cannot know, on an individual Joyce level, if that is the case.”

Cancer treatments can have long-term side effects, he said, “and we don’t know how quickly the tumor would have grown.” The treatment for Hodgkin’s lymphoma is so effective that delaying treatment until she experiences symptoms could have had the same happy outcome.

For now, health experts emphasize that the Grail blood test is not diagnostic of cancer; a positive result triggers further tests and biopsies.

“It’s an avenue in diagnostic testing that has never been tried before,” Kramer said. “Our ultimate destination is a test that has a clear net benefit. If we don’t do it carefully, we will stray from the path.”

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