Princess Kate revealed she is undergoing treatment for a cancer diagnosis. What is preventative chemotherapy?

Catherine, the Princess of Wales, announced Friday that doctors discovered cancer in tests conducted after she underwent major abdominal surgery in January. The 42-year-old princess is now undergoing a course of preventative chemotherapy as advised by her medical team, she said in a video. Here is what that may involve.

Preventative chemotherapy, which is usually referred to as "adjuvant chemotherapy," is an early treatment that is used to reduce the chance of cancer returning, even if all visible cancer was removed in a surgery, according to the Mayo Clinic.