A six-year old Quebec boy who has a brain tumour is responding well after trying out a relatively untested treatment.

In August 2015, a tumour was discovered at the base of Karl Lefebvre’s skull.

It was a ganglioglioma: a rare tumour that grows slowly in the central nervous system and is most frequently found in the temporal lobes of children and young people.

“On the MRI they found this huge tumour, which starts in the brain stem at the top and extends all the way to his cervical spine,” explained Lefebvre’s pediatric neurosurgeon Jean-Pierre Farmer.

The boy’s parents were in shock.

“I don't think any parent wants to hear that their child has a tumour,” said his mother Josée Grenon.

“It was like the end of the world, it feels like you don't have any solutions,” added his father Marc Lefebvre.

Doctors suggested a different route than surgery or chemotherapy, instead suggesting medication called Dabrafenib.

“In a kid like Karl… it's a battle against time, so you choose the best medication that has the chance of working, and that is this pill,” said hematologist-oncologist Nada Jabado.

A pill normally used to treat melanoma, Karl's tumour had a similar mutation.

Doctors had tried it on two other Quebec children with brain tumours.

After three weeks, there was a significant change.

“It showed a dramatic reduction, more than 50 per cent in the tumour,” said Farmer.

“I cried on the doctor,” laughed Grenon.

Karl is the first child to take Dabrafenib prior to undergoing any other treatment, including surgery or chemotherapy.

Even though there was limited research and trials about this pill and its success with brain tumours, Karl’s doctors felt it was his best option.

“We had enough evidence to suggest now was the time to leap forward and to use it upfront,” said Jabado.

“We had that or the surgery, so we took a shot,” said Grenon.

So far it's working. The tumour continues to shrink, but questions remain.

“After we stop the medication, whether the tumour will reappear and at what rate,” said Farmer.

“I hope it doesn't come back,” said Karl – but being a first, no one knows for sure.

“It's a story where we don't have an end yet,” said Farmer.

Karl’s mother, however, is feeling optimistic.

“I know the ending is going to be good,” she said.