Has anyone from the royal family had cancer?

Yes, actually they have.

• Prince Michael of Kent underwent treatment for prostate cancer in 2014.
• King George VI died from lung cancer.
• Princess Margaret died from lung cancer.

There were also others further back in history. You have to keep in mind, the royal family can afford organic foods, proper medications, and top of the line health care. They can also afford the lawyers that will sue for breach of privacy if someone leaks out that they have a medical condition. A few years ago, Prince Phillip did that very thing when a paper falsely reported that he had cancer. The royals do not always want all of their personal business out there for the entire world. They control the media around them pretty tightly where they can.