(BBC) - Former US President Joe Biden, 82, has been diagnosed with prostate cancer that has spread to his bones.Biden, who left office in January, was diagnosed on Friday after he saw a doctor last week for urinary symptoms.The cancer is a more aggressive form of the disease, characterised by a Gleason score of 9 out of 10. This means his illness is classified as "high-grade" and that the cancer cells could spread quickly, according to Cancer Res...