India, May 19 -- Former President Joe Biden has been diagnosed with an aggressive form of prostate cancer, his office announced. The 82-year-old was examined last week after he experienced urinary symptoms, according to a statement Sunday from spokesperson Kelly Scully. The cancer had metastasized to the bone.

"While this represents a more aggressive form of the disease, the cancer appears to be hormone-sensitive which allows for effective management," Scully said. "The president and his family are reviewing treatment options with his physicians."

The press release noted a Gleason score of 9 (Grade Group 5) and metastasis to the bone. Below is an explanation of what a Gleason score of 9 means in the context of this diagnosis.

The Gleas...