Now her son has spoken out to say he believes his mother's life would have been saved had she had a colonoscopy.
Michael Peluso, 31, said other tests "missed" Bellingham's colon cancer, as he spoke publicly for the first time since her death.
"She was a massive champion for getting a colonoscopy. It would have saved her life," he told the Mirror.
"They missed it so much. She had two stool tests, a blood test and they never found it. She was carrying cancer for 18 months before she discovered she had it."
A colonoscopy is a procedure that allows doctors to look at the lining of a patient's large bowel for polyps, inflammation or signs of cancer.
According to the Mirror, Bellingham said before she died: "I always had a stool test and had always gone for a check up but this (cancer) hides.
"Put £1 away for a colonoscopy when you are 60. It's the only way you can know for sure."
Bellingham, 66, known for her role as the Oxo mum and as a Loose Women presenter, had spoken of her plans to spend one more Christmas with her family just days before she lost her battle with cancer.
She was diagnosed last July but in late September disclosed that she had decided to end her treatment to limit the amount of suffering her family would witness.
She died in her husband's arms at a London hospital on October 19.
Her book, 'There's Something I've Been Dying To Tell You', discusses her illness in detail and has spent weeks at the top of the best-seller lists.