Keith Jenkins, 76, from Llandrindod Wells started complaining of a sore neck in the summer of 2018.
He was told the most likely cause of his pain was arthritis.
But after several x-rays and scans, doctors realised he had a cancerous tumour so large, it had snapped part of his spine.
He was unaware he had been living with a broken neck for weeks.
Ambulance and fire crews attended his home in Powys, but it was almost twelve hours before he arrived at his nearest A&E Department over the border in Hereford.
Keith underwent an operation and cancer treatment to remove the tumour, which had become wrapped around his spinal cord.
Both were largely successful, but in April this year he received the news every patient dreads - that doctors had found another tumour.
His family say they are terrified the same will happen again, as Keith is still yet to start his new course of treatment.
First diagnosed with prostate cancer in 2016, daughter Michelle said she believes her father should be a priority.
"My worry is two months ago he had a bit of a sore neck, now he's in pain, so what if it's growing and it breaks and he gets paralyzed?
"It makes me feel angry and upset. I've got a little girl who has a wonderful relationship with my dad and I want him to see her growing up".
Powys Teaching Health Board said they are sorry to hear of the family's concerns, and encouraged anyone worried about their care or treatment to get in touch with their "Putting Things Right" team.