Amber Rose Cliff, whose cervical cancer began silently developing in her late teens, died on Sunday, aged just 25.
The malignancy which was attacking her reproductive system remained undetected for at least three years.
And now, her devastated brother Josh Cliff says there must be more flexibility for women to be screened at a young age on the NHS.
Routine smear testing is only carried out on people over the age of 25.
Josh, 27, says Sunderland-born Amber had begun exhibiting worrying symptoms from the age of 18 and went to the doctors on several occasions.
He understands that she had requested a screening numerous times but was never given one.
Convinced that she needed to be examined, Amber and her family took matters into their own hands.
Josh said: "We went for a private smear test when she was about 21, three years after she'd first been to the doctors.
Amber Rose Cliff died from cervical cancer after being refused a smear test for years
"It turned out that the cancerous tumour in her cervix had been growing for years."
Amber started chemotherapy and radiotherapy and eventually had to have operations to remove parts of her reproductive system.
But despite periods of recovery, the cancer eventually spread to her lymph nodes, lungs and throat.
"She was angry. She felt let down," Josh said.
Thousands of women are diagnosed with cervical cancer every year, according to Cancer Research UK, and it disproportionately effects younger women.
Most health experts agree that routinely screening women younger than 25 would be ineffective.
But Josh believes Amber's experience proves smear tests for women under 18 need to be readily available in certain circumstances, with 20,000 having signed an online petition set up by him.
He said: "I want it to be called Amber's Law."
Any female under 25 showing any problems with their reproductive system should have the option of a cervical screening.
"It shouldn't be mandatory, but that option needs to be there."
Amber was private about her illness, limiting the circle of people who knew what she was suffering to close friends and family.
The Sunderland University business graduate and Gentoo housing officer hid it from those she knew on a daily basis.
Cervical cancer: Women are invited for a screening once they are 25 years old
Josh said: "She didn't want sympathy. She refused to have people feel sorry for her.
"It was hard for the family because we had to pretend everything was okay for her."
Amber's determination to live her life in spite of the disease was undimmed even when her health was in a desperate state, Josh said.
"The Saturday before she died, an ambulance had to take her to hospital because she was having breathing problems.
"But she stood up and got back out of it to go back in to the house and get her make-up bag.
"Amber wouldn't give up - she was always stubborn and it was the best thing she could have been.
"She refused to lie there and die. She was a fighter."
Amid the grief, Josh says he is comforted by the fact he was able to spend one last Christmas with his sister.
Cervical cancer: Amber's brother Josh wants a change in the law to allow under 25s to be screened
He said: "We never even liked Christmas but we had a great one, the best we ever had. The last thing she ever bought was presents for my two children - her two godchildren."
Commenting on the campaign, Dr Jana Witt, health information officer at Cancer Research UK, said screening young women before they reach 25 can "do more harm than good".
She said: "Cervical screening is for women who don't have any symptoms and is an important way to prevent the disease from developing.
"Research has shown that, on balance, screening women under the age of 25 can do more harm than good.
"This is because cervical changes that screening detects in younger women tend to clear up by themselves and are less likely to develop into cancer, so screening may lead to unnecessary tests and treatment.
"Whatever your age or screening history, if you notice symptoms such as bleeding between periods, after sex, after the menopause, or any other unusual changes, it's really important to contact your GP and get them checked out."