Tennis champion Chris Evert said Thursday that her ovarian cancer had returned, and that she had already undergone surgery for the recurrence. 

"I have always believed in being open and honest about my health journey," Evert wrote in a social media post. "This past weekend, after undergoing CT and PET scans, I learned that my ovarian cancer has returned."

Evert did not specify what kind of surgery she had received. She said that the procedure was "the first step" in her latest treatment. Her care will include chemotherapy in the coming weeks, she said. 

The former professional tennis player and 18-time Grand Slam winner is considered a legend of her sport, and one of the most successful players of all time, having been ranked first in women's singles by the Women's Tennis Association for 260 weeks after the rankings launched in 1975. 

The association, which is the main organizer of women's professional tennis globally, describes Evert's standout career as "the stuff of legend" and notes how her backhand form "revolutionized" the game.

Evert said the recurrence will prevent her from attending Wimbledon this year. Although retired from the court, Evert is often seen courtside at the world's largest matches or appearing as a broadcaster or commentator. The upcoming Wimbledon Championships are scheduled to begin in London next week. 

Evert said she will also step back from other "professional commitments over the next few months to focus on" her health. 

"Ovarian cancer is relentless, but I will stay optimistic and determined in continuing to fight this battle," Evert said. 

Evert was initially diagnosed with ovarian cancer in December 2021. In January 2023, she announced that she was cancer free, but later said the cancer had returned in December of that year.

About 70% of ovarian cancer patients will experience a recurrence of their disease, according to the Ovarian Cancer Research Alliance.