Olivia Munn is opening up about her mom’s breast cancer diagnosis.
The Your Friends and Neighbors star, 45, took to Instagram on Wednesday and revealed that her mom was diagnosed with Stage 1 HER2 breast cancer after Munn’s own breast cancer diagnosis in 2023.
“Going through cancer is really hard,” Munn wrote in a statement shared in the post. “But there’s something about watching a loved one go through it that is even more heartbreaking.”
In the statement, Munn wrote that she “urged my mother and sister to take the Breast Cancer Lifetime Risk Assessment test” after receiving her diagnosis in 2023.
According to the Susan G. Komen foundation, the test is a tool “often used by health care providers to estimate breast cancer risk.”
Dr. Jennifer Ashton, former ABC News chief medical correspondent and a board-certified OB-GYN, said in a 2024 interview that the test “helps to provide an actual numerical risk for lifetime risk of breast cancer and breast cancer diagnosis in the next five years.”
“It is what we use in medicine to stratify a woman’s individual risk in a more precise way,” Ashton added.
According to the American College of Radiology, people with 20% or greater lifetime risk of breast cancer are considered high risk.
Munn said that her mother scored 26.2% on the IBIS, or the Tyrer-Cuzick Risk Assessment test, and because of that score, she wanted her mom to get an MRI, which led to learning about her Stage 1 HER2 breast cancer diagnosis.
The American Cancer Society describes HER2 as a “protein that helps breast cancer cells grow quickly.”
“Breast cancer cells with higher than normal levels of HER2 are called HER2-positive,” the ACS states. “These cancers tend to grow and spread faster than breast cancers that are HER2-negative, but are much more likely to respond to treatment with drugs that target the HER2 protein.”
Munn said her mom “completed 12 rounds of chemo” after her diagnosis “and will continue monthly Herceptin transfusions this fall.”
“I spent many nights taking care of my mom when the chemo became too much, wishing I could fight the fight for her, even if only for a day to give her a little break,” she continued. “It’s no small feat to realize you can’t do it for them. To anyone out there who is taking care of someone or has made it their profession to do so, thank you. These fights can feel near impossible without you.”
Munn said the Tyrer-Cuzick Risk Assessment “saved my life and now my mom’s.”
The Tyrer-Cuzick model, or IBIS, is a type of breast cancer risk calculator. According to the American College of Obstetricians and Gynecologists, this calculator is one of a few options that physicians can use to calculate lifetime risk of breast cancer.
“My mom wanted me to tell you that she hopes by sharing her story it will save someone’s life,” Munn said.
“I want to say how proud I am of my mom,” she added. “She’s handled all of this with bravery and humor while still driving us crazy (just days after her double mastectomy she tried to do laundry and make dinner — she’s insane).”
She thanked “the hospital nurses, patient coordinators and staff who have taken care of my mother,” as well as her mother’s primary care physician and oncologists, before thanking her own doctors as well.
Munn previously opened up about her private battle with breast cancer in a 2024 Instagram post. At the time, she revealed she had been diagnosed with Stage 1 aggressive Luminal B breast cancer in April 2023 and underwent a double mastectomy 30 days later.
Since then, Munn has been open about her experience, sharing her story to urge other women to get tested and to raise awareness about the disease.
“I’m lucky,” she said in her 2024 Instagram post about her diagnosis. “We caught it with enough time that I had options. I want the same for any woman who might have to face this one day.”
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