King Charles III was diagnosed with cancer this year after treating an enlarged prostate. His daughter-in-law, Kate Middleton, completed chemotherapy in September.

King Charles III spoke about the “uncertainties and anxieties of illness” as he delivered his annual holiday message from a former hospital chapel, a poignant location given the king’s ongoing cancer treatment.

King Charles III used his annual Christmas message Wednesday to hail the selflessness of those who have cared for him and the Princess of Wales this year, after both were diagnosed with cancer. The 76-year-old monarch said he and his family are “continually” impressed by those who dedicate their lives to helping others.