Three years ago Perth doctors gave her nine months to live when she was diagnosed with an inoperable Diffuse Intrinsic Pontine Glioma (DIPG) growing in her brain.
Her parents Sandy and Choong Nguyen sold everything, including their home, to fly to Mexico, so Annabelle could undergo experimental cancer treatment.
Now, doctors in Mexico have told her parents scans show the tumour is gone.
“I was just speechless, I couldn't say anything,” Ms Nguyen said.
“I didn’t cry, I didn't laugh, I didn't do anything. I was like, are you serious? It was unbelievable.”
Doctors in Monterrey injected Annabelle with a mix of chemotherapy drugs through a catheter inserted into an artery, sending them directly to the brain tumour.
She had ten treatments, at a cost of more than $300,000. Her parents say they didn't see any results until the seventh treatment.
“There's no tumour, there's no activity in her brain at the moment. So we are very, very thankful and very, very happy,” Ms Nguyen said.
The treatment is not offered in most parts of the world, including Australia, because there are no studies to prove it works and Annabelle’s Mexican doctors have not released their findings.
“We need to be cautious with these sorts of treatments/most times it ends badly,” Telethon Kids Institute brain tumour researcher Nick Gottardo said.
Annabelle still has three months worth of follow up treatments in Mexico, however the family will fly back home to Perth next week.
This article originally appeared on The West Australian.