The princess announced in March that she was being treated for an undisclosed type of cancer LONDON: Catherine, the Princess of Wales, says she has completed chemotherapy and will return to some public duties in the coming months. The 42-year-old wife of Prince William is expected to undertake a light program of engagements until the end of the year. The princess announced in March that she was being treated for an undisclosed type of cancer. Kate attended a ceremonial birthday parade for her father-in-law King Charles III in June, and the following month presented the men’s winner’s trophy at the Wimbledon tennis championships.