Study boosts hope of ‘liq­uid biop­sies’ for can­cer screen­ing

Kuwait Times - - HEALTH & SCIENCE -

Sci­en­tists have the first major ev­i­dence that blood tests called liq­uid biop­sies hold promise for screen­ing peo­ple for can­cer. Hong Kong doc­tors tried it for a type of head and neck can­cer, and boosted early de­tec­tion and one mea­sure of sur­vival. The tests de­tect DNA that tu­mors shed into the blood. Some are used now to mon­i­tor can­cer patients, and many com­pa­nies are try­ing to de­velop ver­sions of th­ese for screen­ing, as pos­si­ble al­ter­na­tives to mam­mo­grams, colono­scopies and other such tests.

The new study shows this ap­proach can work, at least for this one form of can­cer and in a country where it’s com­mon. “This work is very ex­cit­ing on the larger scale” be­cause it gives a blue­print for how to make tests for other tu­mor types such as lung or breast, said Dr. Den­nis Lo of Chi­nese Univer­sity of Hong Kong. “We are brick by brick putting that tech­nol­ogy into place.” He led the study , pub­lished Wed­nes­day by the New Eng­land Jour­nal of Medicine. Lo is best known for dis­cov­er­ing that fe­tal DNA can be found in a mom’s blood, which launched a new era of non­in­va­sive test­ing for preg­nant women.

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 per­cent.

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 per­cent ver­sus only 20 per­cent 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 per­cent at three years ver­sus 70 per­cent 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 US 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 Kong­based 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.—AP

PHILADEL­PHIA: In this file photo, a pa­tient has her blood drawn for a liq­uid biopsy dur­ing an ap­point­ment at a hos­pi­tal in Philadel­phia. —AP

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