Blake Darragh was eight weeks old when he developed nappy rash "almost like a chemical burn", said his mother Amanda Darragh of Holsworthy.
It took five months of pain and discomfort before experts at The Children's Hospital Westmead diagnosed a very rare, fast growing and highly malignant childhood cancer. It was also growing in an even more unusual location: Blake's bladder and prostate.
"You hear that kids have cancer, but you never think it is going to be your child," said Mrs Darragh. "I never saw it as bad luck, I saw it as a piece of crap. It is just something that happened to our family."
Of the 14 to 20 children like Blake who are diagnosed with rhabdomyosarcoma (cancer of the muscle) every year in Australia, four to five have it in the bladder. By the time Blake's was found, it had spread from the bladder into his prostate.
His chance of survival over a five-year period is two in three, said his paediatric oncologist, Dr Geoff McCowage.
Blake, though, is one of six children who have been treated at Westmead with paediatric brachytherapy performed by Dr Jennifer Chard, a pioneering paediatric radiation oncologist in this field.
Treating Blake's cancer involved putting him in an induced coma, because children of his age wiggle too much, and surrounding him with a perspex box to remind everyone that he was fragile.
To deliver strong doses of radiation for intensive treatment from a short distance, allowing more accuracy and less damage to surrounding tissues still growing in a baby, tiny hollow rods were inserted in Blake's groin using equally tiny medical equipment. The radiation was delivered via the rods to the tumour for 10 minutes, twice a day.
Until recently, the federal government sent children to the French hospital Institut Gustave Roussy in Paris for this treatment. Researchers reported in July on a study of a 100 children between five months and 14 years of age who had been treated with a combination of surgery, chemotherapy and radiation delivered using brachytherapy. There was a five-year, disease-free rate of 84 per cent, with overall survival rate of 91 per cent.
"If it had been an 18-year-old , we would have given radiotherapy from outside the body for six weeks, but that would destroy a one-year-old's tissues and the hips, the bones, the intestines," said Dr McCowage.
But the path to diagnosis was painful for Blake, and awful for his family to watch.
Because many children suffer from nappy rash, Blake's doctor thought it was a urinary tract infection, which wouldn't clear with medication.
"He would scream and [the urine] would drizzle out, which was unusual," said Mrs Darragh who also has two older sons, four and six.
"He was extremely uncomfortable, at six months he wasn't sitting up, because he would try to sit up and he would scream and throw himself backwards."
His bladder had nearly four times as much urine than is usual in a baby of his age.
Except for the darkest times, his mother said most people wouldn't have known Blake was sick.
"He smiled through it, this really helped me. He's just a happy little baby," said Mrs Darragh. To get through the toughest year of her life and her marriage, Mrs Darragh relied on her family, her faith and an endless supply of pasta bakes from friends and family.
It is early days yet but Dr Chard said the tumours had shrunk in every child.
Blake is now 21 months old with no sign of recurrence. Doctors say it will take five years before they are sure he is permanently cancer free.
In the meantime, his mother pays more attention to his nappies than she did to her other sons'.
"We have very full nappies," said Mrs Darragh. "I think I'm probably more obsessed with his than I was with his brothers."