Olivia Munn is sharing more details about her breast cancer journey in hopes that it will help someone else going through it. The star has been open about her diagnosis and the treatment she's gone through since revealing she had breast cancer in March 2024.
In a new Instagram post from Sept. 4, she shared a detailed timeline starting with the preventive screenings she went through and ending with the new medication she's taking.
"I thought that I should clearly lay it out for you guys. I hope that by doing so, it helps others who have gone through it or are going through it now maybe feel a little comforted in knowing that I've gone down the same path and I'm doing OK," she said in the clip.
The former "Newsroom" star, 44, previously shared that she wants to raise awareness of the importance of knowing your breast cancer risk and getting the appropriate screenings.
"I was walking around thinking that I had no breast cancer,” she told People magazine in April. “I did all the tests that I knew about.”
“You realize cancer doesn’t care who you are; it doesn’t care if you have a baby or if you don’t have time,” Munn added. “It comes at you, and you have no choice but to face it head-on.”
Here's what Munn has shared about having breast cancer.
Oliva Munn diagnosed with breast cancer
Munn revealed her breast cancer diagnosis in an Instagram post on March 13, writing, “I hope by sharing this it will help others find comfort, inspiration and support on their own journey.”
In the post, Munn explained she was diagnosed with luminal B breast cancer in April 2023 after undergoing a course of genetic tests. At first, she tested negative for the BRCA gene, a mutation commonly linked to breast cancer, and had a clear mammogram.
But when Munn went to see her OB-GYN for her annual pap smear, her doctor calculated her breast cancer risk assessment score and determined she had a 37% lifetime risk of having breast cancer.
So, Munn underwent an MRI, an ultrasound and a biopsy. An MRI found a spot near one of her lymph nodes in her right breast, Munn told People. The ultrasound that followed found two more tumors in her right breast, which turned out to be stage 1 cancer. And after reviewing her first MRI again, doctors confirmed cancer was in her left breast, too.
During surgery, her doctors also found a “tangerine-sized” pre-invasive cancer, Munn told People.
She was set to head to Germany to start shooting a sci-fi film when she found out. “I was not someone who obsessed over death or was afraid of it in any way,” she told People. “Having a little baby at home made everything much more terrifying.”
What is luminal B cancer?
Munn said she had luminal B cancer in both breasts, which she described as “an aggressive, fast moving cancer.”
Doctors and researchers categorize cancer into groups according to genetic information, per the Mayo Clinic. Luminal B breast cancer is estrogen receptor-positive, which means the cancer cells rely on estrogen to grow. So, if estrogen production is stopped with treatment, the cells will ideally stop growing too, according to the National Cancer Institute.
Luminal B is also typically HER2 negative. HER2 is the protein that helps breast cancer cells grow, per the American Cancer Society. When it's negative, that means the cancer isn't likely to respond to drugs that target HER2.
You can also expect luminal B cancer to be progesterone receptor-negative, meaning it won't respond very well to hormone therapy.
"About 15-20% of breast cancers are luminal B tumors," according to Susan G. Komen. "Women with luminal B tumors are often diagnosed at a younger age than those with luminal A tumors."
What is a breast cancer risk assessment?
If it weren’t for her OB-GYN, Dr. Thaïs Aliabadi, Munn said she wouldn’t have been diagnosed for another year. Last year, Aliabadi recommended Munn have her breast cancer risk assessment score calculated. “The fact that she did that saved my life,” wrote Munn.
“A breast cancer risk assessment score is calculated using a mathematical model that incorporates various risk factors that have been shown to be associated with breast cancer,” Dr. Jennifer Plichta, director of the Breast Risk Assessment Clinic at Duke Cancer Institute, previously told TODAY.com.
It can determine your lifetime risk of developing breast cancer and your risk of invasive breast cancer, meaning it spreads outside the milk ducts, of the next five years.
There are at least 24 risk assessment models used to determine someone’s score, according to the Cleveland Clinic. But the most common is the Gail Model which looks at demographic information such as age, race and biopsies, among other considerations. Your doctor can calculate your score for you or you can calculate it using an online tool such as this one from the National Cancer Institute.
Munn and Aliabadi used the free online tool called a Tyrer-Cuzick risk assessment calculator, per People.
Had Munn delayed any longer, Aliabadi said the cancer would have likely grown and "she probably wouldn’t have been early stage."
Munn urged her followers to ask their doctors to assess their likelihood for developing breast cancer. Aliabadi said that if someone's score is higher than 20%, they need annual mammograms starting at 30 years old. Aliabadi also said that she's calculated breast cancer risk for patients as young as 25.
"I want every woman to be their own self advocate at home," Aliabadi said. A mammogram, she added, won't always be enough. "My heart aches when I see these young patients with stage 4 breast cancer," she said, because she believes they could have caught it earlier had they had an assessment.
It's worth noting that the risk assessment tools are population-based and can only determine your average risk among those in your demographic, TODAY.com previously reported. It can’t provide a prediction about whether you'll have breast cancer or not.
What treatment did Olivia Munn have?
Within 30 days of being diagnosed, Munn underwent a series of surgeries. She had "a lymph node dissection, a nipple delay procedure (a surgical procedure which spares the nipples) and a double mastectomy,” when both breasts are removed to reduce the risk of cancer recurring, People reported.
“There’s so much information, and you’re making these huge decisions for the rest of your life,” Munn told People. “I really tried to be prepared, but the truth is that nothing could prepare me for what I would feel like, what it would look like and how I would handle it emotionally. It was a lot tougher than I expected.”
In her March Instagram post, Munn described having four surgeries in the past 10 months.
“I had amazing doctors, but it was still a negotiation sometimes on what we are doing,” she told People. She could have opted out of the nipple delay, which saves the nipples, but chose to go forward with it. “But I’m glad I did. I want to give myself the best shot of keeping the parts of me that I can keep.”
She underwent her breast reconstruction last fall and decided to make her breasts smaller than they were before.
"I know a lot of women want to go bigger, but (I said) go smaller,” she told People. “It’s so important to say what you want out loud — and don’t stop. Even as the anesthesia was making its way into my body, the last thing I said was, ‘Please go smaller.’"
In November 2023, she began hormone suppression therapy to lessen the likelihood that the cancer would return, People reported. The therapy put Munn into medically induced menopause, which brought on several symptoms. “I’m constantly thinking it’s hot, my hair is thinning and I’m tired a lot,” Munn told People.
Munn also underwent surgery to remove her uterus, fallopian tubes and ovaries to stop the production of the hormones that cause her cancer. She said her family, including her almost-3-year-old son, Malcom, was the driving force behind her additional treatments.
“You start thinking about your mortality differently once you have a baby,” Munn told Vogue in May. “It’s his childhood, but it’s my motherhood, and I don’t want to miss any of these parts if I don’t have to.”
Because she and husband, comedian John Mulaney, want more children, she opted to freeze her eggs for a third time, and they have two viable embryos.
When she first announced her diagnosis, Munn gave a raw look at the emotional side of her treatment with a video on Instagram. In it, Aliabadi hugs Munn in a hospital bed dressed in a surgical gown and cap, as Aliabadi tells Munn to do this for her son, as Munn replies, “I’m ready.”
Despite being diagnosed with cancer so young, Munn wrote on Instagram that she feels "lucky. 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."
