When little Charlie Woolley complained of stomach ache, doctors said he was constipated and sent him home.
Then his stomach grew and grew until he was so swollen his mum said he 'looked nine months' pregnant'.
But despite mum Sharon's assertions that there was something seriously wrong with her five-year-old he was repeatedly sent home for a total of 11 times.
It was only after five months, when desperate Sharon refused to budge from a hospital clinic, that the horrifying truth was finally revealed: Charlie had a rare and aggressive form of cancer called neuroblastoma – and it had grown to the size of a basketball.
She said: "All this time when I'd been fighting for someone to take me seriously, cancer was ravaging my son. I was so angry."
Charlie, who has a form of autism, first complained of stomach ache last January. His GP diagnosed constipation. His stomach swelled and doctors repeatedly prescribed laxatives.
By his ninth appointment last May, Charlie 'looked nine months pregnant'.
Sharon, 37, of Lytham St Annes, Lancs, said: "He was in so much pain yet no one would listen to me."
Later that month, Charlie was referred to Blackpool Victoria Hospital where Sharon refused to budge until he'd had a scan. The hospital agreed to give him a CT scan and then sent Charlie to the Royal Manchester Children's Hospital where doctors broke the bad news.
Sharon said: "The doctors told me my boy's tumour was the size of a basketball."
Charlie's cancer was at Stage 4 at which the survival rate is less than 40 per cent. The chances are 80 to 95 per cent at Stages 2 and 3.
Sharon said: "If we hadn't been fobbed off so much for so long, maybe he'd have much better odds today."
The Neuroblastoma Alliance said the cancer was hard to diagnose, but a delay could be significant as tumours can grow 10cm in a fortnight. Blackpool Teaching Hospitals NHS Foundation Trust declined to discuss the case.
Charlie is having chemotherapy and needs an operation. Sharon is raising cash to fund treatment in the US. To help go to travelswithcharlie.org.