Study boosts hope of ‘liquid biopsies’ for cancer screening

The study involved nasopharyngeal cancer, which forms at the top of the throat behind the nose. It’s a good test case for DNA screening because it’s an aggressive cancer where early detection matters a lot, and screening could be tried in a population where the cancer is most common — middle-aged Chinese men.

Also, the Epstein-Barr virus is involved in most cases, so tests could hunt for viral DNA that tumors shed into the blood in large quantities, rather than rare bits of cancer cells themselves.

About 20,000 men were screened, and viral DNA was found in 1,112, or 5.5 per cent. Of those, 309 also had the DNA on confirmatory tests a month later. After endoscope and MRI exams, 34 turned out to have cancer.

More cases were found at the earliest stage — 71 per cent versus only 20 per cent of a comparison group of men who had been treated for nasopharyngeal cancer over the previous five years. That’s important because early cases often are cured with radiation alone, but more advanced ones need chemotherapy and treatment is less successful.

Screening also seemed to improve how many survived without worsening disease — 97 per cent at three years versus 70 per cent of the comparison group.

Only one person who tested negative on screening developed nasopharyngeal cancer within a year.

The researchers estimate 593 people would need to be screened at a total cost of $28,600 to identify one cancer case. It may be worth it in Hong Kong, but maybe not in places like the U.S. where the disease is rare, and more people would have to be screened at a greater cost to find each case, said Dr. Richard Ambinder of Johns Hopkins School of Medicine, who wrote a commentary in the journal.

Still, “this is showing that liquid biopsies have great promise,” he said. “This is an advance that will indeed save lives.”

The study was sponsored by an Asian foundation and the Hong Kong government. Lo and some other authors founded Cirina, a Hong Kong-based company focused on early cancer detection, and get royalties related to DNA blood tests. In May, Cirina merged with Grail Inc., a California company working on cancer screening blood tests with more than $1 billion from drug companies and big-name investors such as Jeff Bezos and Bill Gates.

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Marilynn Marchione can be followed at @MMarchioneAP.

Marilynn Marchione, The Associated Press

by Canadian Press

Study boosts hope of ‘liquid biopsies’ for cancer screening

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