Margaret Beaton, 51, had been treated for urinary infections for two years before medics discovered a tumour in her bladder, in March this year.
The mum-of-three, from Greenock, Inverclyde, eventually underwent two operations and was given chemotherapy and radiotherapy in a bid to treat the illness.
Her heartbroken eldest daughter, Vikki, 30, told how her mum deteriorated rapidly - and felt 'cheated' by her shortened lifespan.
And Margaret's widower, Craig, said his worst fears were confirmed when cancer was diagnosed, despite medics believing the mum was suffering from an infection.
Despite questions over the time taken to get a diagnosis, the family has not lodged a complaint with the NHS and spoke of their gratitude at the care Margaret received.
Mechanic Craig, 51, said: "Margaret was given antibiotics for two years without having any scans.
"Doctors went down the infection route.
"We were told her symptoms were wear and tear and osteoporosis in the spine, when it was cancer."
In February, Margaret was being treated for a bladder infection and given antibiotics, after suffering gynaecological bleeding, despite having had the menopause five years ago.
She pushed for further examination and was diagnosed with bladder cancer.
But later scans showed the disease had spread to her spinal cord and liver.
Margaret died on September 12, at the family home.
She had hoped an operation which removed her bladder and womb would save her life, even if it meant having to use a urostomy bag.
Surgery was performed on May 15 at the Queen Elizabeth University Hospital in Glasgow, and took around 11 hours.
The family claim they were told Margaret would be up and about after the op, but she spent a week in intensive care, and another 14 weeks in hospital.
Two weeks before her death, Margaret was given a second round of chemotherapy and a blood transfusion at the Beatson Cancer Centre.
Margaret, who had worked as a pub manager and also for Amazon, was being cared for in Inverclyde Royal Hospital in J North and got home on September 10, two days before her death.
Vikki said: "We were told the worst case scenario would be that she would have to use a urostomy bag but she would have a good quality of life.
"They tested all the lymph nodes and it came back clear.
"She felt cheated. She had the operation to give her more time and a quality of life.
"She must have had that tumour for a long time but she had never been unwell.
"Two weeks before she died, she was just constantly sleeping and couldn't plan her funeral.
"She didn't have the time to tell us what she wanted to say.
"We were all there when she passed away in my dad's arms.
"She took her last breath knowing she was safe to go - I think that gave him some comfort.
"We weren't ready for it - it happened so quickly.
"My dad feels he has lost half of himself, they were together 31 years.
Margaret's family are still reeling from her sudden death, including Vikki's siblings, Craig, 26, and Amy-Leigh, 16.
And an astonishing 1,000 people turned out for Margaret's funeral.
Vikki added: "The staff in J North did an outstanding job of caring for her but she never opened her eyes again and passed away the day after her 27th wedding anniversary.
"She fought a short battle, but she fought it with everything she had."
And the family are now facing spending Christmas - Margaret's favourite time of year - with a gaping hole in their lives.
Vikki added: "My mum loved Christmas.
"When she was told the cancer was terminal she asked if she would be here for Christmas.
"We have a small but close family and now there is this big hole.
"My mum was everything to everyone - we already knew this but as the days go on without her it's getting harder and harder."
She urged other families to push for answers.
Vikki said: "This could be some other family going through the same thing.
"Go and keep getting more opinions, keep asking questions, push for answers.
"Hopefully this could save another family going through what we're going through."
A spokesman for NHS Greater Glasgow and Clyde said: "Our thoughts are with Mrs Beaton's family at this very sad time. "We would be happy to discuss any issues with her family."