Who's Afraid of Early Cancer Detection? - WSJ - 0 views
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A diagnosis of pancreatic cancer usually means a quick death—but not for Roger Royse, who was in Stage II of the disease when he got the bad news in July 2022. The five-year relative survival rate for late-stage metastatic pancreatic cancer is 3%—which means that patients are 3% as likely to live five years after their diagnosis as other cancer-free individuals. But if pancreatic cancer is caught before it has spread to other organs, the survival rate is 44%.
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some public-health experts think that’s just as well. They fret that widespread use of multicancer early-detection tests would cause healthcare spending to explode. Those fears have snarled Galleri and similar tests in a web of red tape.
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But only a handful of cancers—of the breast, lung, colon and cervix—have screening tests recommended by the U.S. Preventive Services Task Force
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Many companies are developing blood tests that can detect cancer signals before symptoms occur, and Grail’s is the most advanced. A study found it can identify more than 50 types of cancer 52% of the time and the 12 deadliest cancers in Stages I through III 68% of the time.
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The trouble is that this cancer is almost never caught early. There’s no routine screening for it, and symptoms don’t develop until it is advanced. Mr. Royse, 64, had no idea he was sick until he took a blood test called Galleri, produced by the Menlo Park, Calif., startup Grail. He had surgery and chemotherapy and is now cancer-free.
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Mr. Royse visited Grail’s website, which referred him to a telemedicine provider who ordered a test. Another telemedicine doctor walked him through his results, which showed a cancer signal likely emanating from the pancreas, gallbladder, stomach or esophagus.
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An MRI revealed a suspicious mass on his pancreas, which a biopsy confirmed was cancerous. Mr. Royse had three months of chemotherapy, surgery and another three months of chemotherapy, which ended last February. Because pancreatic cancer often recurs, he gets CT and MRI scans every three months. In addition, he has signed up for startup Natera’s Signatera customized blood test, which checks DNA specific to the patient’s cancer and can signal its return before signs are visible on the scans
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Grail’s test likewise looks for DNA shed by cancer cells, which is tagged by molecules called methyl groups that are specific to a cancer’s origin. Grail uses genetic sequencing and machine learning to recognize links between DNA methyl groups and particular cancers
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The test “is based on how much DNA is being shed by tumor,” Grail’s president, Josh Ofman, says. “Some tumors shed a lot of DNA. Some shed almost none.
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ut slow-growing tumors typically aren’t shedding a lot of DNA.” That reduces the probability that Grail’s test will identify indolent cancers that pose no immediate danger.
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Grail’s test has a roughly 0.5% false-positive rate, meaning 1 in 200 patients who don’t have cancer will get a positive signal
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Its positive predictive value is 43%, so that of every 100 patients with a positive signal, 43 actually have cancer
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the legislation’s price tag could reduce political support. According to one private company’s estimate, the test could cost the government $39 billion to $145 billion over a decade. Mr. Goldman counters that analysts usually overestimate the costs and underestimate the benefits of medical interventions.
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Because Grail uses machine learning to detect DNA-methylation cancer linkages, the Grail test’s accuracy should improve as more tests and patient data are collected
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regulators may balk at approving the test, and insurers at covering it, until it becomes cheaper and more reliable.
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How would the FDA weigh the risk that a false positive on a test like Grail’s could require invasive follow-up testing against the dire but hard-to-quantify risk that a deadly cancer wouldn’t be caught until it’s much harder to treat? It’s unclear.
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some experts urge the FDA to require large randomized controlled trials before approving blood cancer tests. “Multicancer screening would entail tremendous costs and potentially substantial harms,” H. Gilbert Welch and Tanujit Dey of Brigham and Women’s Hospital wrote
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Dr. Welch and Mr. Dey also suggested that companies should be required to prove their tests reduce overall mortality, even though the FDA doesn’t require drugmakers to prove their products reduce deaths or extend life. Clinical trials for the mRNA Covid vaccines didn’t show they reduced deaths.
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One alternative is to rely on real-world studies, which Grail is already doing. One study of patients 50 and older without signs of cancer showed that the test doubled the number of cancers detected.
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One recurring problem he has seen: “Epidemiologists are always getting cancer wrong,” he says. “Epidemiologists a decade ago said U.S. overtreats cancers. Well, no, the EU undertreats cancer.”
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A 2012 study that he co-authored found that the higher U.S. spending on cancer care relative to Europe between 1983 and 1999 resulted in significantly higher survival rates for American patients than for those in Europe
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By his study’s calculation, U.S. spending on cancer treatments during that period resulted in $556 billion in net benefits owing to reduced mortality.
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He expects Galleri and other multicancer early-detection tests to reduce deaths and produce public-health and economic benefits that exceed their monetary costs
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Expanding access to multicancer early-detection tests could also help solve the chicken-and-egg problem of drug development. Because few patients are diagnosed at early stages of some cancers, it’s hard to develop treatments for them
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the positive predictive value for some recommended cancer screenings is far lower. Fewer than 1 in 10 women with an abnormal finding on a mammogram are diagnosed with breast cancer.
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Mr. Royse makes the same point with personal force. “I would be dead right now if not for multicancer early-detection testing,” Mr. Royse told an FDA advisory committee last fall. “The longer the FDA waits, the more people are going to die. It’s that simple.”