The six-year-old Ngunnawal resident was diagnosed with stage four neuroblastoma a rare and aggressive cancer four years ago.

She's been in remission twice, but now Australian doctors are out of options.

Her parents, Kirsty and James Lambert, are pinning their hopes on a new antibody therapy trial in Germany. But the treatment doesn't come cheap and they need to raise more than $200,000 if Olivia is to have any chance of celebrating her seventh birthday in January.

Yesterday she was very brave as she started another round of chemotherapy at the Sydney Children's Hospital in Randwick. She asked her four-year-old sister Sarah to hold her hand during treatment.

This time the doctors aren't focusing on a cure they are only offering palliative care.

''I want to go to Germany to maybe try and make the cancer go away,'' Olivia said.

''We don't know if it's going to work but we're hoping that it will.''

The family will need to stay in Germany for at least eight months for six, five-week cycles of immuno therapy. The new therapy teaches the body's own immune system to attack and fight neuroblastoma by targeting a carbohydrate/lipid molecule (ganglioside, GD2) present on the surface of neuroblastoma tumour cells.

Early results show the treatment improves cure rates by 20 per cent. It's been trialled in the United States and is expected in Australia in about a year. But Mr Lambert said Olivia couldn't wait that long. With each relapse the chance of her making a complete recovery grows slimmer.

''Last time the cancer returned the doctors said she had a less than zero point something chance of survival,'' he said.

For more on this story, see the print edition of today's Canberra Times.