In most cancers, the survival rate has risen steadily over the years. But bone cancer is a different story. It mainly affects children and young people, and the survival rate has remained the same for the past 25 years.
More than 450 people are diagnosed with primary bone cancer each year and only about half will survive the next five years.
13-year-old Francesca, from Cullingworth in West Yorkshire, says she was lucky, as it took just a few days to get a diagnosis after she visited her doctor when she was seven.
Symptoms include pain, for example in the leg, which often gets worse at night and better during the day.
And this is the reason parents, and GPs, often dismiss the symptoms: they attribute it to "growing pains".