Charles said it was 'heartening' to hear how news of his own diagnosis had helped 'promote public understanding' of organisations that support cancer patients
The King has expressed his "most heartfelt thanks" to members of the public who have sent him messages of support after he revealed his cancer diagnosis.
In his first public comments since Buckingham Palace announced the news last Monday, Charles said "such kind thoughts are the greatest comfort and encouragement".
"It is equally heartening to hear how sharing my own diagnosis has helped promote public understanding and shine a light on the work of all those organisations which support cancer patients and their families across the UK and wider world," the King said in a written statement.
"My lifelong admiration for their tireless care and dedication is all the greater as a result of my own personal experience."
Charles has been spending his time at Sandringham following his diagnosis, with his wife, Queen Camilla, saying the King is doing "extremely well under the circumstances".
A statement released by Buckingham Palace confirmed the King had been diagnosed with cancer after a "separate issue of concern was noted" during treatment for his benign prostate condition.
The statement added that Charles, who has already started treatment as an outpatient, "remains wholly positive about his treatment".
The palace has not confirmed the type of cancer the King has been diagnosed with, but it is understood he does not have prostate cancer.
Charles has postponed all public-facing duties, but is continuing with behind-the-scenes work on his red boxes of state papers. No date has yet been set for the King's return to full public duties.
His eldest son and heir, Prince William, may step in to represent his father at an event, but no engagements are scheduled at the moment and the royal palaces will make arrangements if the need arises.
William's wife, the Princess of Wales, left hospital herself last Monday, having undergone abdominal surgery.
Kate returned to Adelaide Cottage, in Windsor, to be reunited with her three children, but she is not expected to return to official duties until after Easter.
Macmillan Cancer Support said it had seen a "King Charles effect" with a surge in visits to its website, since the King's diagnosis was made public.
The charity said Charles' openness about his cancer diagnosis meant its information and support pages saw 48,304 hits last Monday - representing a 42% increase on the same day last year and the highest daily figure since at least March 2020.
This is the Royal Rota - our weekly podcast about the royal family, with ITV News Royal Editor Chris Ship and Producer Lizzie Robinson.