Sam Dorrance was so excited about starting primary school that he spent the summer of 2015 counting down the days.

"He used to ask me, 'Mummy - how many more sleeps until big school?'," said his mother, Tanya Dorrance. "He couldn't wait".

When the day finally arrived, however, something was wrong.

Mrs Dorrance, from Stonehaven in Aberdeenshire, said: "He was getting ready for his first day of school when he suddenly vomited, out of the blue.

"From there he very quickly deteriorated with this random vomiting and really severe headaches at the back of his head.

"He would point to the back of his head and scream 'my head hurts'. Then there was his balance - he wasn't able to stand up."

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By the weekend, Sam was sleeping most of the day, waking up only to "scream in pain, throw up and fall asleep again".

Mrs Dorrance, a midwife, sought help from her GP surgery where a doctor initially diagnosed tonsillitis and suggested Sam "just doesn't want to go to school".

Days later, a second GP carried out a physical examination but admitted she was baffled and advised Mrs Dorrance to come back if nothing changed.

On her third appointment, ten days after symptoms had first begun - by which time Sam was so sick his mother had to carry him into the practice - Mrs Dorrance demanded a referral to the children's hospital in Aberdeen.

The Herald: Sam Dorrance with mother, Tanya, and father, GraemeSam Dorrance with mother, Tanya, and father, Graeme (Image: Dorrance family)

A CT scan revealed a tumour the size of a small plum close to Sam's brainstem, and he was immediately transferred by ambulance to Edinburgh where doctors diagnosed a high-grade medulloblastoma.

"The most common age for diagnosis is five and it's more common in boys than girls," said Mrs Dorrance.

"He had the classic symptoms - balance problems, morning vomiting, headaches."

Following surgery, Sam was due to begin intensive radiotherapy when he collapsed with extreme brain swelling. 

His parents were told he was going to die.

Mrs Dorrance said: "He was admitted to intensive care.

"They put him on a ventilator and said even if he did survive, he'd be severely brain damaged - they had never seen this in a child before and didn't know what had caused it.

"They wanted us to turn the ventilator off. This was only six weeks after his diagnosis."

The Herald: Sam underwent a gruelling regimen of surgery, radiotherapy and chemotherapy, but died in July 2016Sam underwent a gruelling regimen of surgery, radiotherapy and chemotherapy, but died in July 2016 (Image: Dorrance family)

Following advice from cancer specialists in England, Sam was placed on high-dose steroids and low-dose chemotherapy and amazed medics when he woke up - apparently recovered - two weeks later.

Fearful of potential side effects, however, doctors postponed the start of radiotherapy until December 2015, followed by four months of chemotherapy from February to June 2016.

Tragically, the treatment was unsuccessful, and Sam died - aged five - in July 2016.

Mrs Dorrance said: "At the end of the four months they re-scanned him and found that he didn't have any tumours in his brain, but it had spread to his abdomen and he had cancer cells in his cerebrospinal fluid that surrounds the brain and spinal cord.

"Within 10 days he had passed away. It was very quick."

The Herald: Mrs Dorrance said her son's experience had driven her to raise funds for research into brain tumours, which she said were underfunded compared to other forms of cancerMrs Dorrance said her son's experience had driven her to raise funds for research into brain tumours, which she said were underfunded compared to other forms of cancer (Image: Dorrance family)

Mrs Dorrance added: "He basically became unresponsive and very confused at home. 

"I took him into the children's hospital in Aberdeen, they scanned him and found multiple small tumours scattered all over his brain.

"That's how aggressive his cancer was. We took him home and he died the next day."

A fundraising drive spearheaded by the Dorrance family - including Sam's 21-year-old brother and father, Graeme Dorrance - has now raised more than £191,000 for The Brain Tumour Charity, with a target of £200,000.

Mrs Dorrance said: "The one thing I discovered is that brain tumours are so underfunded, and yet it's one of the biggest killers of adults under 40 and children in the UK and around the world. 

"That was the driving force for why we set up Super Sam's Fund, because all of the money goes towards research into aggressive brain tumours like the one Sam had.

"So much money is being spent on breast cancer, and breast cancer has a great survival rate now - which is fantastic - but something needs to be done for these other cancers with a really poor outcome. We're way behind."