Buckingham Palace has announced the news
The Palace confirmed the disease, which is not prostate cancer, was discovered while the King was being treated in hospital for an enlarged prostate.
The King has started a schedule of regular treatments, but has been advised to postpone his public-facing duties.
The Palace declined to confirm the type of cancer.
He will carry on working behind the scenes on state business and official papers, and returned from Sandringham to London on Monday to commence treatment as an out-patient.
Buckingham Palace said in a statement: “During The King’s recent hospital procedure for benign prostate enlargement, a separate issue of concern was noted.
“Subsequent diagnostic tests have identified a form of cancer.
“His Majesty has today commenced a schedule of regular treatments, during which time he has been advised by doctors to postpone public-facing duties.
“Throughout this period, His Majesty will continue to undertake State business and official paperwork as usual.
“The King is grateful to his medical team for their swift intervention, which was made possible thanks to his recent hospital procedure.
“He remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible.
“His Majesty has chosen to share his diagnosis to prevent speculation and in the hope it may assist public understanding for all those around the world who are affected by cancer.”
Charles, 75, was discharged from the London Clinic a week ago after undergoing treatment on an enlarged prostate.
The shock news is the latest health scare to hit the royal family at the start of 2024, coming after the King’s hospital stay, the Princess of Wales’s major abdominal surgery and Sarah, Duchess of York’s diagnosis of skin cancer.
Buckingham Palace announced on January 16 that the King was to have treatment for an enlarged prostate, but that the condition was benign.
The Palace announced the King’s cancer diagnosis at 6pm on Monday.
Charles, who acceded to the throne just 17 months ago, was last seen on Sunday when he attended church in Sandringham.
Published: by Radio NewsHub