A TEENAGE boy has vowed to "rip out" a needle giving him a blood transfusion despite a judge ordering the lifesaving treatment against the boy's religious beliefs.

Doctors from Sydney Children's Hospital in Randwick made an urgent application to the Supreme Court to help them save the boy, a devout Jehovah's Witness, who is fighting Hodgkin's disease.

In a judgment handed down on March 28, Justice Ian Gzell immediately ordered a blood transfusion after doctors said the 17-year-old's life depended on it.

Justice Gzell noted his orders "may only extend (the boy's) life for 10 months - when he becomes an adult and may stop the treatment".

"The sanctity of life in the end is a more powerful reason for me to make the orders than is respect for the dignity of the individual," he said.

The boy, who cannot be identified, was diagnosed with Hodgkin's disease in January last year. He is a "devoted" follower of the religion and Justice Gzell found him to be "cocooned in that faith".

The boy told doctors he did not want to be given blood, even in an "emergency", and that if he was forcibly transfused while sedated it would be like being "raped".

Doctors had respected his wishes, with the teen treated with chemotherapy in order to avoid giving him transfusions. But that did not reduce the tumours in his lungs, spleen and lymph nodes.

His doctor, Professor Glenn Marshall, argued the boy needed a high dose of chemotherapy, but that would make him anaemic and he would require a transfusion.

Professor Marshall told the court that, if he continued to treat the boy's cancer with chemotherapy and he was not transfused, he had an 80 per cent chance of dying.

"The alternative is that (the boy) will die of cancer because he is receiving less than optimal treatment for it," Justice Gzell said.

Professor Marshall said the boy had a 50 per cent chance of being cured of cancer if he was given full treatment, including a transfusion.

His father has written a scripture quote which refers to abstaining from blood on a whiteboard in his hospital room. The court was told "it is a tenet of the Jehovah's Witness faith that blood products are forbidden".

The boy and his father told the court there were no "ramifications" from their church provided the transfusion was "against his will".

The boy told the court taking blood would change his relationship with God.

The judge has given the green light for doctors at the Kids Cancer Centre at Randwick (part of the Sydney Children's Hospital) to give the boy blood.

The boy was in remission from the disease for several months last year but he suffered a relapse in November.

Last year the NSW Supreme Court made similar orders for a four-year-old girl from South Australia.

Originally published as Doctors can save Jehovah's Witness