Former President Joe Biden has been diagnosed with an "aggressive" form of prostate cancer that has spread to his bones. But what does it mean for this type of cancer to be called aggressive?

Joe Biden’s cancer diagnosis has raised big questions about his health and future. At 82, the former president is battling metastatic prostate cancer, which doctors say has already spread to his bones.

Prostate cancer is one of the most common types of cancer in men and grows very slowly, says NLM. Chances of a diagnosis increases with age.