Testing probe to help can­cer sur­geons know they got it all

Re­search team hope to make use of ex­per­i­men­tal de­vice by early next year

St. Thomas Times-Journal - - LIFE - LAURAN NEERGAARD THE AS­SO­CI­ATED PRESS

WASH­ING­TON — Pa­tients emerg­ing from can­cer surgery want to know, “Did you get it all?” Now sci­en­tists are de­vel­op­ing a pen-like probe to help sur­geons bet­ter tell when it’s safe to stop cut­ting or if stray tu­mour cells still lurk.

The de­vice is highly ex­per­i­men­tal, but lab­o­ra­tory tests show it uses molec­u­lar fin­ger­prints to dis­tin­guish be­tween can­cer­ous cells and healthy ones far faster than to­day’s tech­nol­ogy, Texas re­searchers re­ported Wed­nes­day.

“That’s re­ally anyone’s worst night­mare, to go through surgery and know there’s a chance” some can­cer re­mains, said as­sis­tant chem­istry pro­fes­sor Livia Eber­lin of the Univer­sity of Texas at Austin, who is lead­ing the work. “By pro­vid­ing real-time molec­u­lar in­for­ma­tion, we could re­ally im­prove ac­cu­racy.”

Her team aims to be­gin testing the de­vice dur­ing surg­eries, start­ing with breast can­cer, early next year.

When sur­geons think they’ve re­moved all of a tu­mour, they of­ten also re­move a thin layer of sur­round­ing tis­sue, called the mar­gin, to be sure no can­cer cells linger at the edge and in­crease the risk of re­lapse.

The prob­lem: That check takes time, for pathol­o­gists to process the tis­sue and ex­am­ine it un­der the mi­cro­scope. For cer­tain es­pe­cially tricky tu­mours, sur­geons some­times pause for a half-hour to more than an hour, the pa­tient still un­der anes­the­sia, to await the re­sults. For breast can­cer and cer­tain other types, of­ten the an­swer doesn’t ar­rive un­til a few days af­ter surgery, rais­ing the pos­si­bil­ity of re­peat op­er­a­tions.

In con­trast, “our de­vice is able to give an im­me­di­ate read­out in un­der a minute,” said UT re­search en­gi­neer Noah Giese.

How it works: Cells pro­duce unique sets of small mol­e­cules that per­form var­i­ous func­tions — and thus also act as fin­ger­prints. Re­searchers place the pen-like de­vice di­rectly onto tis­sue, press a foot pedal to switch it on, and a tiny amount of wa­ter emerges to gen­tly pull mol­e­cules from the cells in that spot.

A tube car­ries the droplet to a ma­chine called a mass spec­trom­e­ter that iden­ti­fies mol­e­cules by cal­cu­lat­ing their mass. Soft­ware then im­me­di­ately an­a­lyzes whether the re­sult­ing fin­ger­print matches can­cer or healthy tis­sue.

In lab tests of sam­ples that had been taken from 253 pa­tients with lung, ovary, thy­roid or breast tu­mours, the so-called MasSpec Pen was more than 96 per cent ac­cu­rate in di­ag­nos­ing can­cer, re­searchers re­ported in the jour­nal Sci­ence Trans­la­tional Medicine. They also suc­cess­fully used the pen dur­ing a hand­ful of op­er­a­tions on mice.

“It’s in­trigu­ing tech­nol­ogy,” said Dr. Nita Ahuja, chief of sur­gi­cal on­col­ogy at Johns Hop­kins Medicine, who wasn’t in­volved in the work.

If it pans out, doc­tors would have to place the pen on mul­ti­ple spots to check an en­tire wound. Re­searchers noted it doesn’t ap­pear to harm tis­sue, mean­ing pathol­o­gists still could dou­ble-check with stan­dard tech­niques when hu­man testing be­gins.

UNIVER­SITY OF TEXAS AT AUSTIN/AP

Sci­en­tist Jial­ing Zhang as he demon­strates us­ing the MasSpec Pen to an­a­lyze a hu­man tis­sue sam­ple. Sci­en­tists are de­vel­op­ing a highly ex­per­i­men­tal pen­like probe to help sur­geons bet­ter tell when it’s safe to stop cut­ting or if stray tu­mor cells still lurk.

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