Kate Middleton Is Undergoing Preventative Chemotherapy. What That means

Preventative chemotherapy is often used after surgery to "decrease the likelihood" that cancer will return.

Catherine, Princess of Wales, announced on Friday that she is undergoing preventative chemotherapy to treat cancer discovered after she had abdominal surgery.

While the exact situation is difficult to determine because the 42-year-old princess did not disclose the nature of the cancer, here is an explanation of preventative chemo.

- What is chemotherapy? -