A dangerous form of bone cancer is often being misdiagnosed by GPs as growing pains, a charity has warned.
Just 42% of people who develop osteosarcoma, which mostly affects children and young adults, will survive for five years after diagnosis, the Bone Cancer Research Trust (BCRT) said.
The charity has called for faster X-ray referrals by GPs after a report found survival rates for primary bone cancer have remained unchanged for the past 25 years.
The report, from the National Cancer Intelligence Network, found that while five-year survival rates for almost all forms of cancer have improved in England between 1985 and 2009, there has been no improvement in the survival statistics for primary bone cancer.
Dr Harriet Unsworth, information and research officer at the BCRT, said: "Primary bone cancer symptoms can include painful bones or swollen joints, and this can easily be misdiagnosed by GPs as a sporting injury or growing pains.
"Many children and young adults have had to make several visits to their GP over many months before they are finally sent for an X-ray, or referred to a specialist.
"That can have a huge impact on their chances of survival.
"There is clearly a need to improve GPs' awareness of primary bone cancer so that a quicker diagnosis can be made.
"Faster diagnosis and new treatment options have boosted the survival chances of people with many of the more common forms of cancer. We need to urgently address the imbalance here and find ways to improve primary bone cancer patients' chances of survival."
The charity said that 500 people in the UK are diagnosed with primary bone cancer each year.
The disease affects mainly the arms and legs, but also the skull, pelvis and spine.