Catherine, the Princess of Wales, says she is undergoing preventative chemotherapy after cancer was discovered following abdominal surgery earlier this year. The former Kate Middleton announced the news in a video message released Friday.

Word of her diagnosis followed months of speculation about the 42-year-old princess' health — speculation that only grew when a doctored image of Kate and her children was released by Kensington Palace earlier this month.

"I am well," Kate said in the video. "I am getting stronger every day by focusing on the things that will help me heal."

Do we know what type of cancer Kate has?

Kate did not specify what type of cancer she was diagnosed with. She said she was undergoing preventative chemotherapy on the advice of her medical team.

"It has been an incredibly tough couple of months for our entire family, but I've had a fantastic medical team who've taken great care of me," she said in the video, which palace officials said was filmed Wednesday.

"In January, I underwent major abdominal surgery in London, and at the time it was thought that my condition was non-cancerous," she continued. "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 preventative chemotherapy, and I am now in the early stages of that treatment."

CBS News chief medical correspondent Dr. Jon LaPook said it sounded like her cancer was found early.

"You always want to find cancer in the earliest stages," LaPook said. "They went in there to do whatever procedure they were going to do, and they knew it was going to be some prolonged recovery, and in there, presumably when they were able to take a good look, they didn't see any evidence of cancer. And it was only afterwards, when I guess there maybe was an examination of a specimen, a surgical specimen, that they said, 'Oh, there's some cancer here.'"

He added, "Since you always want to find cancer in the earliest stages, whatever kind of cancer it is, to me that was a relatively good piece of news."

What is preventative chemotherapy and how does it work?

Dr. Shivan Sivakumar, associate professor in oncology at the University of Birmingham, told The Associated Press it's unclear what the princess meant by "preventative" chemotherapy, but he presumed that it's what is known as "adjuvant" chemotherapy in the medical profession.

"This is chemotherapy after an operation to prevent recurrence," he said. "This is to attempt to destroy any circulating cancer cells."

LaPook said "preventative" chemotherapy typically means treatment "preventing growth of microscopic cancer cells."

Preventative chemotherapy can have side effects, including making someone tired, LaPook noted. Other side effects may include nausea, tingling in the hands and feet, and sometimes hair loss, Dr. Monica Avila of Moffitt Cancer Center in Tampa, Florida, told The AP, adding that there are medications to help address side effects.

"A patient can take anywhere from a few weeks to a month or two to recover from those effects," Avila said.

LaPook said he spoke with a cancer expert from NYU Langone Health, where he is a professor of medicine, who shared a positive outlook on the prospects for treatment. 

"He said, yeah, it can be a rough three months or so, for example, but then people tend to have 100% recovery afterwards in terms of getting their strength back and getting back to normal function," LaPook shared.

What else do we know about Princess Kate's cancer diagnosis?

Kate did not share additional details about her condition, asking the public for "time, space and privacy" as she focuses on her treatment and recovery. She also spoke about the challenges of sharing this news with her three young children.

"This of course came as a huge shock, and William and I have been doing everything we can to process and manage this privately for the sake of our young family," Kate said in the video message. "As you can imagine, this has taken time. It has taken me time to recover from major surgery in order to start my treatment. But, most importantly, it has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them, and to reassure them that I am going to be OK."

Kate's news comes not long after her father-in-law, King Charles, announced in February that he would be undergoing treatment for an unspecified form of cancer which was discovered as he was being treated for an enlarged prostate. Charles' wife, Queen Camilla, said he is "doing extremely well under the circumstances." 

King Charles said in a statement Friday that he is "so proud of Catherine for her courage in speaking as she did," and said he had remained in the "closest contact with his beloved daughter-in-law throughout the past weeks."

In:
• British Royal Family
• Kate Middleton

Sara Moniuszko

Sara Moniuszko is a health and lifestyle reporter at CBSNews.com. Previously, she wrote for USA Today, where she was selected to help launch the newspaper's wellness vertical. She now covers breaking and trending news for CBS News' HealthWatch.

Twitter