Tests help doc­tors tai­lor treat­ment for kids with brain tu­mours

Truro Daily News - - CANADA - By Sheryl UBelacker

At eight years old, Ju­lia Van Damme was like most other kids her age — go­ing to school, play­ing sports and goof­ing around with her younger sis­ter and older brother. But a rou­tine eye exam turned up a baf­fling and un­ex­pected find­ing — she was vir­tu­ally blind in one eye.

An MRI showed Ju­lia had a golf ball-sized tu­mour in her brain, and the pres­sure it was ex­ert­ing on her op­tic nerve was de­stroy­ing the sight in her left eye.

“I didn’t no­tice I was los­ing vi­sion at all, be­cause I was young,” said Ju­lia, now 12. “I didn’t know what a brain tu­mour was. I didn’t know what can­cer was then, so it was pretty hard for me to un­der­stand.”

A biopsy of her tu­mour at Toronto’s Hospi­tal for Sick Chil­dren de­ter­mined Ju­lia had what’s known as a low-grade glioma, a pe­di­atric brain can­cer that af­fects about 25,000 to 30,000 chil­dren world­wide.

Be­cause of its lo­ca­tion in the cen­tre of her brain, above the pi­tu­itary gland, the tu­mour couldn’t be re­moved sur­gi­cally, and ra­di­a­tion in the area car­ried too high a risk of long-term ef­fects. So Ju­lia was started on stan­dard chemo­ther­apy, a gru­elling 18-month course of weekly in­tra­venous in­fu­sions, which in the end was in­ef­fec­tive in shrink­ing her tu­mour.

But doc­tors at Sick Kids had an­other trick up their prover­bial sleeves: tests they had de­vel­oped to an­a­lyze the molec­u­lar makeup of in­di­vid­ual brain tu­mours showed Ju­lia’s can­cer was be­ing driven by a sin­gle ge­netic mu­ta­tion called a BRAF V600E.

Re­search had shown that pe­di­atric gliomas with this ge­netic sig­na­ture of­ten re­spond well to a drug used to treat adults with ma­lig­nant melanoma, a po­ten­tially deadly form of skin can­cer.

For al­most two years, Ju­lia has been able to keep her tu­mour from pro­gress­ing by tak­ing two pills in the morn­ing and two at night — an oral reg­i­men that was un­heard of just a few years ago.

“In the past, we used to treat kids with brain tu­mours just based on look­ing at the tu­mour, by how the cells looked (un­der a mi­cro­scope) and by look­ing at the imag­ing,” said Dr. Uri Ta­bori, a neuro-on­col­o­gist at Sick Kids. “We did all tu­mour types sort of the same.”

But in the last decade, re­searchers be­gan to be able to de­lin­eate tu­mours into sub­types based on their ge­netic pro­file, al­low­ing them to pre­dict how each sub­type was likely to be­have given a spe­cific treat­ment.

“Then we re­al­ized that us­ing th­ese molec­u­lar tools, we can ac­tu­ally tai­lor treat­ment to some pa­tients that’s dif­fer­ent than oth­ers,” said Ta­bori, who treated Ju­lia. “We can say for your tu­mour, it’s go­ing to be very, very low-grade, slow-grow­ing, and we should re­frain from any toxic ther­apy. And for the other ones, we need to be more ag­gres­sive.

“And the last part of that, which is amaz­ing, is that some tu­mours will ac­tu­ally have pills that tar­get the mu­ta­tion. So in­stead of giv­ing chemo­ther­apy, ra­di­a­tion and ag­gres­sive surgery, you can just give the pill and the tu­mour will re­spond and the pa­tient will get bet­ter.”

Dr. Cyn­thia Hawkins, a neu­ropathol­o­gist at the hospi­tal, has been at the fore­front of de­vel­op­ing the molec­u­lar tests to help doc­tors bet­ter di­ag­nose and treat spe­cific sub­types of child­hood brain can­cers, among them glioma and medul­loblas­toma, a fast-grow­ing ma­lig­nancy that ac­counts for about 20 per cent of all child­hood brain tu­mours.

“One of the is­sues that we run into with pe­di­atric brain tu­mours, in par­tic­u­lar, is that al­though some com­mer­cial en­ti­ties have de­vel­oped tests for adult brain tu­mours, most of them don’t do it for pe­di­atrics be­cause the num­bers just aren’t big enough to make it fi­nan­cially vi­able,” Hawkins ex­plained.

“And most of th­ese tests we had to de­velop from the ground up at Sick Kids,” she said, adding that hos­pi­tals across Canada, as well as from the U.S. and coun­tries around the world now send tu­mour sam­ples to the Toronto hospi­tal for molec­u­lar anal­y­sis.

While Ju­lia is do­ing well — the oral med­i­ca­tion Dabrafenib ini­tially shrank her tu­mour by about 15 per cent and its size has since sta­bi­lized — her di­ag­no­sis sent the Mis­sis­sauga, Ont., fam­ily on a jour­ney they never ex­pected to take.

“We were shocked,” said her fa­ther, Dan Van Damme, es­pe­cially since Ju­lia had never in­di­cated she was hav­ing trou­ble see­ing, had an A av­er­age at school and had con­tin­ued to play soc­cer and hockey, even some­times tak­ing a turn as a goalie.

Even through her weekly rounds of chemo, Ju­lia main­tained an up­beat de­meanour, said her mother Maureen. “She’s a trooper, she’s a tough kid and she never com­plained about ‘Why her, why do I have to do this?’

“She was al­ways smil­ing. We’d skip down the hall­ways to go get chemo,” she re­called. “She just has such a strong spirit and a great at­ti­tude.”

Be­fore Ju­lia went into the hospi­tal to have a biopsy of her tu­mour, her brother Dylan, now 14, and sis­ter Clara, 9, went up to their rooms and each brought her a stuffed an­i­mal to take with her.

“The bond the three of them made and the five of us made dur­ing this jour­ney is ‘We’re in it to­gether,’” said Maureen, a stay-ath­ome mom. “That was from Day 1 our motto: we’re in this to­gether, you’re not alone.”

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