Blood tests for cancer pose a risk to those who use them

Susan Iorio Bell, April 18, 2022, Fort Fort, Pa., Received a disturbing result using a blood test for cancer, but the scan found no signs of cancer. (Brian Anselm / New York Times)

Jim Ford considers himself a lucky man: Experimental blood tests revealed that he had early stage pancreatic cancer. It is one of the deadliest cancers in the world and is found too late.

After the scan, biopsy and surgery, followed by chemotherapy and radiation, 77-year-old Ford, who lives in Sacramento, California, has no cancer.

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“As my doctor said, I won the lottery,” he said.

Tests such as diagnosing him have been praised by President Joe Biden, who has made them a priority in his anti-cancer program. The bill, which has 254 co-sponsors in Congress, would allow Medicare to pay for the tests as soon as the Food and Drug Administration approves them.

But companies do not expect regulatory compliance. One, GRAIL is selling its annual test, the list price is $ 949, and another company, Exact Sciences, expects to receive a lawsuit using a procedure called lab-developed tests.

Tests for small fragments of cancer DNA or proteins are the new frontier of screening. The companies that develop them say they can find dozens of cancers. Standard screening tests are commonly used to detect breast, colon, cervical, and prostate cancers, but 73% of cancer deaths are undiagnosed with standard tests.

Proponents say these tests reduce the number of cancer deaths and that tumors are small and curable. However, more than 1 million healthy adults are tested for cancer every year to determine whether they should have a blood test for cancer. Results take ten years or more.

“We are now in the early days of blood tests,” the doctor said. Thomas Bir, a cancer researcher at the University of Oregon Health and Science, is leading a GRAIL-funded study of a Ford cancer test. “Some people may choose to be informed early on.”

Companies want to get tests approved with less rigorous research than the FDA requires, and if they do, they can make big profits.

“GRAIL offers an annual trial of every Medicare beneficiary, which makes it a screening test that will bankrupt Medicare,” said Dr. H. Gilbert Welch, Brigham and Senior Investigator, Center for Surgery and Public Health, Women’s Hospital.

An annual test of 44 million Medicare beneficiaries and about $ 1,000 per year, as well as expensive scanners and biopsies for those who test positive, could be a significant price tag.

He and other critics warn that the risks of releasing the tests are significant. As paradoxical as it may sound, early detection of cancer can lead to many deaths without early diagnosis. Because, at least with current treatment – killer cancer is not necessarily cured if detected early.

And there are other risks. For example, some people get a positive test, but doctors cannot find a cure for cancer. Others are aggressive with cancer or chemotherapy for cancer, and if left alone, they can grow, spread, and even disappear.

The beer blood test admits that “there is no risk or cost and it cannot diagnose every cancer.”

But he said: “I think there is a promise that will have a real impact.”

Other experts are concerned.

Dr. Barnett Kramer, a member of Lisa Schwartz’s Truth Foundation in Medicine and former director of the National Cancer Institute’s Department of Cancer Prevention, fears that tests will never be widely used without showing their usefulness. When that happened, he said, “It’s hard to ring the bell.”

“I hope we haven’t had half of a nightmare,” Kramer said.

Damocles syndrome

Susan Iorio Bell, a 73-year-old nurse living in Fort Fort, Pennsylvania, immediately registered on Facebook when she saw an advertisement for her to hire women her age to submit to a blood test for cancer. This is in line with his belief in prophylactic medicine and clinical trials.

The study, now owned by Exact Sciences, included a test involving women with Geisinger in the healthcare industry. The test looks for proteins and DNA spilled by tumors.

Bell’s findings were alarming: he had alpha-fetoprotein in his blood, which could indicate liver or ovarian cancer.

He was worried; Her father had colon cancer and her mother had breast cancer.

Bell saw what happened when patients had a terrible prognosis. “All of a sudden, your life can change in a day,” he said.

However, positron emission tomography or PET, scan and MRI of the abdomen did not detect the tumor. Was the test false positive or was the tumor too small? It is impossible to know yet. Bell undergoes regular cancer screening to monitor liver function.

“I just go every day,” he said. “I am a man of faith, and I believe that God has a plan for me. For better or for worse, it is his will. ”

According to some cancer experts, Bell’s experience shows concern about blood tests. The situation may affect only a small percentage of people, as most test takers say they have not been diagnosed with cancer. Scanners or biopsies can often detect it among those whose tests detect cancer.

However, Dr. Susan Domchek, a breast cancer researcher at the University of Pennsylvania, warns that when a large number of people are tested, false positives become a “real problem” and “we need to know what to do with these results and what they mean.”

Dr. Daniel Hayes, a breast cancer researcher at the University of Michigan, called the condition “Damocles syndrome.”

How good are the tests?

So far, Geiser’s study is the only one published on the question of whether a blood test can detect early, undetected cancers.

In addition to Bell, the study involved 10,000 women between the ages of 65 and 75 who submitted blood tests and encouraged cancer screening.

Blood tests found 26 patients with cancer: two lymphomas, one thyroid cancer, one breast cancer, nine lung cancers, one kidney cancer, two colorectal cancers, one appendix cancer, two uterine cancers, six ovarian cancers and one. It is unknown whether there were cancer cells in the woman’s body, but it is unknown where the cancer started.

Seventeen or 65% of these women were in the early stages of the disease.

Normal screening found an additional 24 cancers that did not have a blood test.

Dr. Bert Vogelstein, a cancer researcher at Johns Hopkins Medicine who helped develop the test, said the study was not designed to show risks and benefits. This requires much larger and more detailed research.

The GRAIL study, led by Beer, involved 6,629 participants. His temporary data, presented at a professional meeting last year, showed that the test found signs of cancer in 92 participants. After these subjects underwent additional tests such as CT and PET scans and biopsies, the researchers concluded that there were 29 cancers. Of these, 23 were new cancers and nine were in the early stages. The rest have reappeared in people who have already been diagnosed with cancer.

A 12-month follow-up is ahead, Bir said.

“We are particularly interested in the false-positive question,” he said. “We know what happens when people get a cancer test, but no cancer is found. Is there cancer that develops clinically in the next six months?

“The goal here is to reduce cancer morbidity and mortality,” one said. “It’s a noble and important endeavor.”

Overdose treatment?

When GRAIL was first formed, its leaders invited Donald Berry, a statistician at the MD Anderson Cancer Center in Houston, to become a member of its scientific council.

“They said they needed to be skeptical,” Berry said. “I told them I was skeptical and I was very negative. I told them that this was a real obstacle; they have to undergo very large clinical trials and the end point has to be survival. They need to show that early detection of cancer is not early detection of cancer. That should make sense. ”

A few years later, the company reorganized its scientific advisory board, which included many new experts, and Berry became a member. He doesn’t know why.

“Because they are so generous, I would say that they don’t need my experience,” Berry said. “Honestly, they’re tired of hearing me complain that early detection of cancer isn’t enough.”

But he and other critics have tough questions.

One of them is over-diagnosis: finding small tumors that have never been seen and caused no harm. Some cancers simply do not grow or are eliminated by the body’s immune system. However, without knowing whether cancer is dangerous or dangerous, people are treated as if they were undergoing severe or debilitating and unnecessary therapies.

According to Cramer, this can also be done with standard screening tests, which can actually remove thyroid, breast or prostate glands for benign small tumors.

There are several thought-provoking examples, for example, a screening test for infants, which was once widely used for neuroblastoma and adrenal cancer in Japan, found benign tumors but missed the deadly ones.

But, Kramer added, blood tests look for dozens of cancers, and “it gets worse.”

“We’re getting deeper and deeper into the iceberg of the disease,” Kramer said, adding that “it may look like cancer to the pathologist, but it may not have a natural history at all”.

Kramer adds that the most aggressive cancers cannot be found early to cure. Tumors that release the most DNA and protein into the bloodstream are the largest.

“There is a real value in accepting them until we know they work,” the doctor said. David Rensohoff is a cancer researcher at the University of North Carolina.

What evidence is sufficient?

Vogelstein agrees that a randomized clinical trial is needed. But, he said, it won’t take 20 years. It was supposed to be big, but he said “there is no need to wait to show that it will reduce deaths.” The last points in the middle may be enough, he said, and Exact Sciences, the company he runs the test on, is discussing the proper design of the test with the FDA.

Dr. Joshua Ofman, president and chief medical officer of GRAIL, said the company was working with institutions in the UK and had launched a study that should have yielded results within a few years. There are 140,000 people registered who will be randomized to take the GRAIL test along with standard cancer screening tests or take standardized tests. The goal is to see a reduction in metastatic cancer in those who take the GRAIL test.

“We’re looking forward to finding him,” he said of the cuts.

Berry, however, is restless and fears that the public’s belief in early detection – what he calls “religion” – will rule the day, even if there is no good evidence.

“Everyone loves early detection, but there’s a downside to it,” Berry said.

“Damage, we know,” he added. “The benefits are very unknown.”

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