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

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.

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.