The six-year-old arrived back home on Thursday after life-saving surgery in Melbourne. She relished sleeping in her own bed, watching a Barbie movie with her old sisters, Brynn, 10; and Inge; eight; and doing the school-drop off on Friday,

They were moments of peace in what has been a 15-month race to save Freyja's life.

And mounting the campaign has been her mother Lizzie Christiansen Young, determined to never give up on her daughter and to try every avenue possible to fight the rare, aggressive, confounding cancer growing in Freya's neck.

Lizzie and her girls - she is a single mum to Freyja, Brynn and Inge - are a tight unit. Inge shed a few tears to see her little sister home again. It has been a long and difficult battle for them all.

Freyja's health journey stretches across different hospitals, states and treatments. And it is not over yet.

While the Melbourne surgery at the Epworth hospital in Richmond was successful in removing tumours that had always been on the left-hand side of her neck, a post-operation review revealed some devastating news: the hint of a tumour growing on the right-hand side of the Freyja's neck.

Freyja always required further treatment. There were still active cancer cells on the left, even after the removal of the tumours.

This latest development is likely to mean more time in hospitals, and for a longer time than they hoped. She may have similar surgery to that in Melbourne when robotics were used to remove the tumour via her mouth. Immunotherapy may be enough to shrink the tumour. It all means more time on the precipice for the family.

"I thought I could take my foot off the pedal but given this news, I have to put my foot flat to the floor," Lizzie said, on Friday.

"It means another year and another year is quite daunting but I am optimistic."

The race for a cure for Freyja all started around Christmas, 2016. The girls were enjoying a holiday program riding horses at the National Equestrian Centre.

It was while washing off mud from another fun day that Lizzie discovered a lump on Freya's neck.

That lump was what is now know as a clear-cell sarcoma, extremely rare in children. But it took a long time to get the diagnosis, with doctors as far afield as the Harvard Medical School consulted.

Doctors believed the tumour was inoperable.

"Thirty-seven surgeons said they wouldn't touch her," Lizzie said, this week.

And the best treatment for it - proton therapy - was limited to a few locations worldwide.

Australia would begin a trial of proton therapy in 2020.

That was too late for Freyja.

Immunotherapy at the Sydney Children's Hospital in Randwick was used to reduce the size of the tumours. The family uprooted and lived close by at the Ronald McDonald House .

Lizzie, meanwhile, looked at possible treatment overseas, in Prague, Germany, the United States and Mexico.

She also helped with the fundraising effort to finance any future trip overseas; keeping Freyja's story front and centre of people's minds, mainly through social media.

It was a case of "running, cycling, baking, begging and hoping". Doing anything to raise a dollar.

Her friends raised funds doing everything from auctioning MotoGP memorabilia - a letter hand-written by multiple world champ Valentino Rossi went for $40,000 - to holding special music nights.

Her uncle Darren started a GoFundMe page for Freyja's treatment which has so far raised $92,500.

Even friends back in Lizzie's home country of England did things such as hold fundraising fun runs and Freyja's Fitness Bootcamp in Maroubra raised more than $3000.

In the meantime, Freyja's story drew the attention of even the likes of Wonder Woman actress Gal Gadot who sent her a special message.

When Freyja was being treated at the Sydney Children's Hospital, the singer Seal came to perform for the kids.

Those kinds of special things helped to keep Freyja positive.

But Lizzie knew they were just the soft, touchy-feeling stories around the real issue: her youngest daughter's precarious hold on life.

"When she was diagnosed around December, 2016, we were told people with her kind of sarcoma last five to eight months," Lizzie said.

"That was revised in February the next year when it was confirmed it was actually clear-cell sarcoma and we were told she had five months, at best. And that we needed to do something to make a difference.

"And here she is. That's the absolute miracle of it all."

Lizzie has much praise for Dr Antoinette Anazodo, a paediatric oncologist at the Sydney Children's Hospital and Prince of Wales Hospital, who led the charge for the initial treatment of Freyja.

Dr Ben Dixon at the Epworth Richmond performed on Freyja late last month the Australia-first pharyngeal surgery by robot.

He said Freyja's young age, the type of cancer and the hard-to-reach location of the main tumour - between the carotid artery and the base of the skull - made the surgery unique.

And now Freyja has two more leading oncologists on her side - Professor Grant McArthur a radiotherapy expert, and Dr Greg Wheeler, immunotherapy expert, at the Peter MacCallum Cancer Centre in Melbourne.

"They are the dynamic duo," Lizzie said.

Freyja will head to Melbourne again next week to prepare for more radiotherapy and possibly a year of immunotherapy. Further surgery may be an option.

It means more time away from her home and her school, at Yarralumla Primary. The MissingSchool project founded by Megan Gilmour has provided WonderBot which helps Freyja to connect with her classmates remotely.

Lizzie said the option of overseas treatment is looking more remote. They simply don't have the funds. Treatment in Melbourne is their hope, their beacon.

In the meantime, Freyja plays in her backyard in a cubby house put up during a working bee to create a garden for her, the effort led by Members of the C3 Church Monash and the Canberra Raiders. It's a chance for her to be a child again.

If you would like to help Freyja, go to https://www.acureforfreyja.com/how-to-help