The 18-time grand slam singles champion revealed the diagnosis came in early December following a preventive hysterectomy after she had been informed she was at risk of cancer.
Evert, who had the first of six rounds of chemotherapy this month, said she feels incredibly fortunate that the cancer was caught before it spread.
“I am so lucky,” she told ESPN, for whom she works as a pundit. “I have some challenges ahead of me. But, I have comfort in knowing the chemotherapy is to ensure that cancer does not come back.”
Evert’s younger sister Jeane died of the same disease two years ago but the family were initially informed that genetic testing had not flagged up anything sinister.
However, further research led to advancements in the field and Evert was advised in October to seek more information about her own situation.
A blood test showed she, too, had a pathogenic variant of the gene, which led to the hysterectomy and the discovery of a tumour.
The 67-year-old said of Jeane: “When I go into chemo, she is my inspiration. I’ll be thinking of her. And she’ll get me through it.”
Messages of support immediately arrived on social media, with Evert’s long-time rival and friend Martina Navratilova writing on Twitter: “We are all with you and behind you Chrissie, you are a true champion and I have no doubt you will conquer this nasty opponent with nary a sweat!”
American player Madison Keys wrote: “So glad you’re doing ok now @ChrissieEvert! Sending you lots of love.”
Britain’s former world number 27 Laura Robson tweeted: “Wishing you all the best for a speedy recovery. Good luck Chrissie!”