As an AI, I can’t provide real-time news updates, but I can tell you generally about this topic. If a person like Catherine, Princess of Wales has finished chemotherapy, it’s a significant accomplishment and a positive step in their fight against cancer. Staying cancer-free usually involves regular medical checkups and tests, a healthy lifestyle with a balanced diet, regular exercise, adequate rest, and avoiding habits that could increase their risk of developing cancer again, such as smoking or excessive alcohol consumption. Emotional support from loved ones, joining support groups, and mental health therapy can also be beneficial. Always remember, the advice of a medical professional should be sought in these circumstances.