A Melbourne family ventures into an ethical minefield.

Australian Story: By Emily Porrello and Belinda Hawkins

Ten years ago, Nicola and Jim Walker received the news every parent dreads when their then-two-year-old daughter Abby was diagnosed with leukaemia. It prompted the couple to take a controversial course of action: to fall pregnant with another child and harvest stem cells from the baby’s umbilical cord in case Abby relapsed and needed a transplant.

A family’s determination
After surviving cancer, Abby Walker no longer dreams of being a doctor or a nurse. She wants to be a hairdresser when she is older.

But the 11-year-old’s ordeal did lead to an unexpected bonus — a baby brother.

Abby was two when she was diagnosed with acute lymphoblastic leukaemia (ALL), the most common childhood cancer, after suffering from recurring back pain and bruising.

Although her mother had a sneaking suspicion that more than growing pains were at play, nothing prepared her for the fear she and her husband felt as they watched Abby struggle with the effects of chemotherapy.

“I can remember I had to always get this tube up my nose and I hated it,” Abby said.

A chance remark by a nurse prompted the Walkers to have another child in the hope cord blood stem cells from the new baby would save their daughter if the standard drug regime failed.

The family gave permission for Australian Story to film with them as they embarked on this unusual and controversial solution.

Abby’s mother Nicola Walker said she would do anything to save her daughter’s life.

“You just want to make sure that your baby’s going to be OK,” she said.

Chance leads family to stem cell option
Abby’s senior oncologist and head of Monash Children’s Hospital Cancer Centre, Dr Peter Downie, said she had an 80 per cent chance of survival using chemotherapy and most likely would never need a stem cell transplant.

“I didn’t think that we’d ever need the stem cells because my expectation was that she would be cured,” he said.

Dr Downie said although collecting stem cells from the umbilical cord and placenta was not unusual, having another child for that reason was “not the right thing to do”.

But for the Walkers, any chance of losing their only daughter was enough to justify a “back-up plan” and within a year of Abby’s diagnosis, Nicola was pregnant with their fourth child.

“It was always going to be an option that we were going to hopefully have another one,” Abby’s father Jim Walker said.

“With Abby’s diagnosis, I suppose it sort of hurried the process on a little bit.”

Dr Downie said there was only a 25 per cent chance the baby’s stem cells would be a match for Abby, which they would only test if she relapsed and needed a transplant.

“It’s not something that we do lightly. It’s a treatment of last resort,” he said.

Baby James’s stem cells in storage
A stem cell transplant involves administering high doses of chemotherapy (and sometimes radiotherapy) to destroy the cancerous cells in the bloodstream and bone marrow.

New stem cells infused via a drip eventually settle in the bone marrow and begin producing healthy blood cells.

When baby James was born, it was up to Mr Walker to deliver the stem cells to the Royal Children’s Hospital in Melbourne. They remain in storage eight years later.

“Thankfully Abby hasn’t relapsed so we’ve never had to use the stem cells,” Mr Walker said.

Mrs Walker said they did not know whether the stem cells were a match, but as time goes on she did not want to “tempt fate”.

The Walkers said they stood behind their decision to store James’s stem cells for Abby, but Mrs Walker said she felt some regret for James, now eight, who has been asking questions about his birth.

“There were a few people who were against it, the fact that this baby may be brought into the world and made to think that it was born just in order to help Abby,” Mrs Walker said.

“I was quite concerned that as he gets older he may feel that that’s the only reason I had him, but I will explain to him that’s not the case.

“He’s just brought so much love and happiness when we went through such a horrible, horrible dark journey.”

A decade of medical advances
Ten years since Abby’s diagnosis, doctors say cure rates for Abby’s cancer are now well above 90 per cent and, for low-risk patients, almost 100 per cent.

Chair of the Australian and New Zealand children’s haematology/oncology group Dr Chris Fraser said improving cure rates were due to ongoing clinical trials of standard chemotherapy.

“These sorts of results… are really based upon the same medications being used in different ways,” he said.

“There are more options than there ever have been for a patient with ALL that’s not responding to conventional therapy.”

Melbourne Royal Children’s Hospital children’s cancer centre chair Dr Francoise Mechinaud said both new drugs that targeted specific changes in leukaemic cells and experimental genetic engineering techniques that cause the patient’s own immune system to attack cancer cells, were “breakthroughs” for children who relapse or fail to enter remission.

Dr Mechinaud said stem cell transplants had also undergone a revolution in the last two years as parents can now donate stem cells to their children despite only being a “half match”.

“Basically, if we want, we can transplant anyone,” she said.

The Walker family moves on
The Walkers said they have left the stem cell debate behind them and have tried to move on from Abby’s leukaemia. Indeed, Mrs Walker now wants to become a foster parent to help others less fortunate.

“I’ve consciously tried to withdraw from being around cancer,” Mrs Walker said.

“I just don’t want to go back there.”

Abby now sees Dr Downie once a year to monitor her development and check for any unpredicted side effects of chemotherapy.

According to Dr Downie new research showed children could experience some cognitive difficulties caused by exposing the brain to chemotherapy.

“It’s quite frightening to think that there are side effects, different things that could happen to Abby that I wouldn’t want,” Mrs Walker said.

“But in the same hand she is alive and she survived it.”

For the Walkers, cancer is now in the past, but Mrs Walker said she still fears the worst when Abby has a sore back or painful knees.

“It’s the first thing that springs into my mind,” she said.

“I do think, is this her relapsing?”

Dr Downie is confident that Abby is cured.

“Her disease isn’t going to come back,” he said.

“I would be gobsmacked if it did.”

For people wanting to donate bone marrow or blood, contact the Australian Bone Marrow Donor Registry and Australian Red Cross.

Watch Abby’s Road tonight at 8:00pm on Australian Story on ABC.

This post originally appeared on ABC News.