A young Perth girl who captured the hearts of people across the nation has lost her brave battle with cancer.

Amelia ‘Milli’ Lucas was diagnosed with an aggressive brain tumour in 2016.

Generous West Australians and her family raised $170,000 for surgery with Sydney neurosurgeon Dr Charlie Teo.

The 2019 operation successfully removed 98 per cent of the tumour to help prolong Milli’s life.

Milli celebrated her 14th birthday last month and her family revealed her condition had deteriorated.

Dr Teo told 6PR’s Mark Gibson the news of her passing hit him hard.

“I was really devastated, I sort of stopped dead in my tracks when I heard the news … it really had a pretty powerful impact on me,” he said.

“My patients always show amazing courage, and when they die it always takes a little bit out of me, but with Milli it was something else.”

Dr Teo said the 14-year-old had “the X-factor” and “was always smiling.”

“There was that sort of a positivity about her, her engagement with the people around her, her courage.”

The radical surgery to remove the Grade VI Glioblastoma was labelled inoperable by WA doctors.

“It was a terrible tumour that extended into the brain stem, an incredibly sensitive, eloquent part of the brain,” he said.

He hopes Milli’s legacy will help raise awareness about the horrific disease.

“With the public support … and people like Milli showing us how huge an impact this disease has on society, then hopefully we can get some answers and cures for a terrible, terrible disease.”

Click play to hear the full interview.