According to Sean Coughlan, King Charles III diagnosed with cancer, Buckingham Palace says: 

King Charles has been diagnosed with cancer. The specific type of cancer hasn’t been disclosed, except that it’s not prostate cancer. This diagnosis came to light during treatment for an enlarged prostate. Starting Monday, King Charles, who is 75 years old, has begun undergoing regular treatment sessions and will temporarily step back from his public responsibilities.

Despite this setback, the Palace shared that the King is very optimistic about his treatment and eagerly anticipates resuming his full range of public activities as soon as he can. Details about the cancer’s stage or expected outcomes have not been released.

King Charles has personally informed his two sons of his health situation. The Prince of Wales is reportedly keeping in close touch with his father. Meanwhile, Prince Harry, who resides in the US, has already spoken with his father and plans to visit him in the UK soon.

As for the King’s duties, he returned to London from Sandringham, Norfolk, on Monday morning and has started his treatment as an outpatient. While his public appearances will be on hold, King Charles will carry on with his essential duties as the nation’s head of state, which includes managing paperwork and conducting private meetings.

Should there be a need, the constitution allows for “counselors of state” to step in for the monarch. Currently, this group includes Queen Camilla, Prince William, the Princess Royal, and Prince Edward, with Prince Harry and the Duke of York no longer serving in these roles due to their status as non-working royals.

In related news, Prince William has also been away from the public eye, supporting his wife, Catherine, the Princess of Wales, during her recovery from abdominal surgery.

Source : BBC