It’s aggressive. The cells have an ugly, disordered appearance under a microscope. Pathologists gave them a Gleason score of 9 (out of 10) for their likelihood to advance quickly. The cancer has already moved from Biden’s prostate to his bones, which means it cannot be cured — only controlled with drugs.

President Joe Biden's "aggressive" prostate cancer has led to renewed interest in his health during his presidency

The announcement Sunday that former President Joe Biden was diagnosed with advanced prostate cancer has some people wondering how the disease could have been missed.