Catherine, Princess of Wales, is undergoing treatment for cancer, she shared in her first public address since retreating from the public eye after surgery earlier this year.
The former Kate Middleton, 42, revealed in a rare video March 22 that she's in the early stages of preventive chemotherapy. In her message, Kate said that when she underwent planned abdominal surgery in January, "it was thought that my condition was non cancerous."
"The surgery was successful. However, tests after the operation found cancer had been present. My medical team therefore advised that I should undergo a course of preventive chemotherapy and I'm now in the early stages of that treatment," the princess said.
“It has taken me time to recover from major surgery in order to start my treatment,” she added.
Kate went on to share that she and her husband, Prince William, have assured their children — George, 10, Charlotte, 8, and Louis, 5 — that she's "going to be OK."
"As I've said to them, I am well and getting stronger every day by focusing on the things that will help me heal in my mind, body and spirits."
Prince Harry and the former Meghan Markle, U.K. Prime Minister Rishi Sunak and Princess Diana's brother, Charles Spencer, all sent well wishes to Kate.
“We wish health and healing for Kate and the family, and hope they are able to do so privately and in peace,” the Duke and Duchess of Sussex said in a statement.
Here's what to know about Kate's diagnosis — and what it means to get preventive chemotherapy.
What type of cancer does Kate Middleton have?
Kate did not specify what type of cancer she has.
Dr. Ben Ho Park, director of precision oncology at Vanderbilt School of Medicine, tells TODAY.com that the most common type of cancers to be discovered from abdominal surgery are gastrointestinal, urinary and genital.
But given the information that's currently available, "it could be anything," he says.
What is preventive chemotherapy?
While not a technical, clinical term, preventive chemotherapy refers to treatment that is conducted after an initial treatment, like surgery, to prevent cancer from coming back, Park explains. A medical term for it would be "adjuvant chemotherapy."
"There are some cancers ... where we have to make decisions (as to) who should get additional chemotherapy after surgery and who should not," Park says. "We base that off things like the stage of the cancer, the type of cancer, and even ... the age of the patient sometimes to determine whether or not giving chemotherapy after surgery will improve outcomes."
With preventive chemotherapy, "even though the surgeons have removed everything they can see, there could still be cancer cells floating around in the body that, if left untreated, may come back later (and) is then incurable," he adds.
While the palace has not confirmed what kind of cancer Kate's doctors found following her surgery, adjuvant or preventive chemotherapy is “typically used for breast, colon, ovarian or lung cancer,” Dr. Tara Narula, NBC medical contributor, explained during a TODAY segment on March 25. And treatment, she added, typically lasts between three and six months.
While IV infusions that administer chemotherapy are common, Kate might be taking any form of it, including a pill, said Narula. "It's any of the available chemotherapy agents that we use for any advanced cancer," she says. "So it may be a different duration and intensity, but these are the same drugs that carry the same potential toxicities."
As far as side effects, Kate might experience "fatigue, decreased appetite, nausea, vomiting, diarrhea, bleeding, bruising, infections," Narula says. And long term, the princess, like anyone who undergoes this treatment, might experience cardiovascular complications, fertility issues and any number of effects to her organs.
While Kate's age might help her tolerate these side effects better, Narula says there's no guarantee. "This is not a walk in the park. When we say the term preventive, it sounds light and fluffy, but she may be going through a lot this time," Narula notes.
Clinical trials have shown that chemotherapy after initial treatment for some cancers can reduce the risk of the cancer recurring, he says.
Although Park has no inside knowledge of Kate's case, he believes the preventive chemotherapy she is undergoing is "trying to maximize" on the treatment she's already received, with the goal of eliminating all the cancer cells.
Does Kate Middleton have cancer?
It's not clear whether Kate Middleton currently has cancer.
Kate received a cancer diagnosis and underwent abdominal surgery in January, and is currently in the "early stages" of preventive chemotherapy, she said in her announcement.
For many people who receive preventive, aka adjuvant, chemotherapy, Park says it's not clear if they have cancer in that moment, and sometimes afterward.
"In truth, we over treat patients every year because we simply don't know (if they still have cancer)," he explains. "A lot of patients ... get chemotherapy when they're probably already cured."
"There's so much uncertainty," he adds. And even after preventative chemotherapy, patients and their doctors "will still not know" if the cancer will recur.