King Charles III wrote to former President Biden after he announced he was diagnosed with an “aggressive form” of prostate cancer, Buckingham Palace confirmed to NewsNation on Monday.

Biden’s personal office on Sunday announced that the former president “was seen for a new finding of a prostate nodule after experiencing increasing urinary symptoms.”

“On Friday he was diagnosed with prostate cancer, characterized by a Gleason score of 9 (Grade Group 5) with metastasis 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. The President and his family are reviewing treatment options with his physicians.”

The news comes as the former president, 82, has stepped back into the spotlight following the end of his term earlier this year, and it has raised questions on whether warning signs could have been caught earlier.

The British monarch, 76, is undergoing his own treatment for an unspecified form of cancer, which was diagnosed in early 2024. He stepped away from public duties for about three months after his diagnosis but continued fulfilling state duties, including reviewing government papers and meeting with the prime minister.

In March, the king was hospitalized after experiencing “temporary side effects’’ related to a scheduled cancer treatment, Buckingham Palace said at the time.

“Following scheduled and ongoing medical treatment for cancer this morning, The King experienced temporary side effects that required a short period of observation in hospital. His Majesty’s afternoon engagements were therefore postponed,” Buckingham Palace released in a statement.