‘X-Men’ Actress Olivia Munn, 45, is navigating breast cancer recovery while raising two young children, candidly sharing the mental and emotional toll of juggling treatment and motherhood. In an Instagram post, she described the everyday chaos many moms face, even though she’s also dealing with breast cancer treatment.
After undergoing a double mastectomy for luminal B breast cancer, Munn continues to speak openly about the complexities of reconstruction, survivorship, and maintaining a sense of normalcy.
Hormone therapy is used for hormone receptor-positive cancers. These types of cancers are the most common types of breast cancer. Hormone receptor-positive means the cancer or tumor needs the hormones estrogen and/or progesterone to grow and flourish.
Hormone therapy works by driving the estrogen levels down or blocking the estrogen’s ability to interact with the estrogen receptor on the cancer cell.
The side effects of hormone or endocrine therapy can mimic menopause. Depending on the endocrine or hormone medication, each one may have its own side effects, which may include: bone and joint pain, fatigue, nausea and/or vomiting, and constipation.
Munn was diagnosed with breast cancer despite a “normal” mammogram and testing negative for the BRCA gene mutation, which elevates the risk for breast and ovarian cancer. At the request of her OBGYN, Munn underwent a Breast Cancer Risk Assessment, which led to the discovery of her cancer after additional screening.
Actress Olivia Munn is no stranger to multitasking, but in 2025, she’s juggling more than most: raising two young children while recovering from breast cancer. In a recent post, she shared an honest moment many moms will recognize.
“Going from 1 to 2 kids broke my brain,” she wrote in an Instagram post while showing off a barrage of reminder notes.
“The other day, I took Malcolm to swim class 3 hours too early because I thought it was Wednesday, but it was Friday…I admit that carrying a tote bag of paper notes and reminders is no way to live. Please flood my comments with advice,” she continued.
Supportive fans chimed in, though some were more helpful than others.
“I have no advice cause I have a chaos tote as well and prefer things on paper than my phone,” Instagram user Gabrielle wrote.
Perhaps Kathryn Lubbe was more helpful by adding a helpful tip that coincides with doctors’ appointments.
“I have found scheduling my tasks alongside appointments helps a lot,” Lubbe said.
Her words reflect the mental load so many mothers carry—now compounded by the physical and emotional toll of breast cancer treatment. Munn, who underwent a double mastectomy after being diagnosed with luminal B breast cancer, has been candid about the challenges of recovery, parenting, and maintaining a sense of normalcy.
WATCH: What Happens During a Double Mastectomy?
A double mastectomy is a procedure in which both breasts are removed to get rid of cancer. The procedure may also be performed as a preventative measure for women who are at a very high risk of developing breast cancer.
The procedure typically only takes a few hours, but it may take longer depending on what type of reconstruction a woman has opted to get. Some women decide to have their breasts reconstructed and have implants put in right after the mastectomy, while others don’t have reconstruction at all.
“A double mastectomy typically takes about two hours for the cancer part of the operation, the removal of the tissue,” Dr. Elisa Port, Chief of Breast Surgery at Mount Sinai Health System, tells SurvivorNet. “The real length, the total length of the surgery, can often depend on what type of reconstruction [a patient] has.”
NEW YORK, NEW YORK – OCTOBER 01: (L-R) Elizabeth Hurley and Olivia Munn light the Empire State Building pink with a scrolling ribbon in the mast to honor the Esteé Lauder companies’ Breast Cancer Campaign and Breast Cancer Awareness Month on October 01, 2025, in New York City. (Photo by John Nacion/Getty Images for Empire State Realty Trust)
Munn’s raw honesty shines a light on the realities of survivorship and motherhood. It’s a reminder that behind every treatment is a woman still trying to make it to swim class on the right day—and that’s just as heroic.
Olivia’s Breast Cancer Diagnosis & Its Impact on Other Women
Munn, despite receiving a clear mammogram, learned she had an aggressive form of cancer in both of her breasts after receiving a breast cancer risk assessment. She credits the cancer risk assessment for saving her life.
The Breast Cancer Risk Assessment Tool, also called the Gail Model, allows doctors to estimate a woman’s risk of developing invasive breast cancer over the next five years.
John Mulaney and Olivia Munn pictured at the 2025 Vanity Fair Oscar Party on March 02, 2025, in Beverly Hills, California (Photo by Neilson Barnard/Getty Images for Vanity Fair)
Munn says that since going public with her cancer journey, she continues to be approached by other women who are now asking their doctors about the cancer risk assessment since learning of Munn’s, including a young mother of three.
“Every time I go out, there’s at least one person…there was this woman who’s young. She has three kids, and she says because of my story, she went out and took the test and learned she has stage 0 breast cancer,” Munn explained in an Instagram story.
“We both had this moment, I know what you’re going through, but we’re so excited that you found it early,” Munn continued.
“It’s hard to explain knowing that this diagnosis that put so much fear into me has been able to be turned into something that’s saving people’s lives,” Munn told “Meet the Press” host Kristen Welker.
Since Munn shared her story publicly, the National Cancer Institute attributes an uptick in women inquiring about a cancer risk assessment to the “X-Men” actress.
How Munn Was Introduced to the Breast Cancer Risk Assessment
“I wouldn’t have found my cancer for another year – at my next scheduled mammogram – except that my OBGYN…decided to calculate my Breast Cancer Risk Assessment Score. The fact that she did save my life,” Munn said in an Instagram post.
The Breast Cancer Risk Assessment she credits for catching her breast cancer is a “statistical model that allows healthcare professionals to calculate the probability of a woman developing breast cancer over the course of their lifetime,” Dr. Ruth Oratz, breast medical oncologist, NYU Langone Health’s Perlmutter Cancer Center; clinical professor of medicine, NYU Grossman School of Medicine, tells SurvivorNet.
(@oliviamunn/Instagram)
Last year, she wanted to be proactive about her health and underwent genetic testing.
Genetic tests can be as simple as a saliva swab or a blood sample. The results help your care team determine if you have a specific mutation that puts you at higher risk for cancer. The results help doctors tailor treatment and are helpful for breast cancer patients.
“I tested negative for all (different cancer genes), including BRCA,” Munn said.
Olivia Munn at the 96th Annual Academy Awards on March 10, 2024, in Hollywood, California (Photo by JC Olivera/Getty Images)
The BRCA1 and BRCA2 gene mutations are among the most important genes to look for in breast cancer. Together, they are responsible for about half of all hereditary breast cancers. These genes prevent cells from dividing haphazardly and uncontrollably in a person without mutations. Mutations prevent these genes from doing their job and can allow unchecked growth of breast, ovarian, and other tissues.
However, two months after undergoing genetic testing, Munn was diagnosed with Luminal B breast cancer in both of her breasts.
According to research in “Breast Cancer,” luminal B tumors are of a “higher grade” and tend to have a worse prognosis. This type of breast cancer is estrogen-positive (ER), meaning the hormone estrogen fuels it. It can also be progestogen (PR) negative, meaning it is not fueled by progestogen. This type of breast also tends to have a higher expression of the Ki67 protein, making it grow quickly. Hormonal therapy and chemotherapy are often used to treat this type of cancer.
Luminal is one of several types and is distinguished by its molecular makeup. Other types of breast cancer include:
Luminal A breast cancer
Luminal B breast cancer
Luminal B-like breast cancer
HER2-enriched breast cancer
Triple-negative or basal-like breast cancer
Each type has a specific, individualized molecular structure. The different types of molecular structure of breast cancer may inform the treatment path.
Munn’s Hormone Therapy
For many women diagnosed with breast cancer, the disease is fueled by hormones—specifically estrogen or progesterone. These are known as hormone receptor-positive cancers, and they represent the most common subtype of breast cancer.
“For women who have hormone-positive breast cancer, it means that they have a cancer that needs estrogen to grow,” Dr. Elizabeth Comen, medical oncologist at Memorial Sloan Kettering Cancer Center, explained to SurvivorNet.
Hormone therapy is designed to block or lower the hormones that help cancer cells grow. It’s a cornerstone of treatment for hormone receptor-positive breast cancer, and it plays a vital role in both treatment and prevention.
“Endocrine therapy has significant benefits in reducing the risk of breast cancer recurrence and improving breast cancer survival,” says Dr. Eleonora Teplinsky, head of Breast Medical Oncology at Valley Health System.
These therapies work in two main ways:
Lowering estrogen levels in the body
Blocking estrogen receptors on cancer cells so the hormone can’t fuel tumor growth
WATCH: Hormone Therapies for Breast Cancer: Aromatase Inhibitor
Types of Hormone Therapy
One widely used drug is Tamoxifen, which blocks estrogen’s ability to bind to cancer cells. It’s used not only to treat breast cancer but also to help prevent it in women with a strong family history or other risk factors.
Another class of drugs, called aromatase inhibitors, works by stopping the body from producing estrogen altogether. These are typically prescribed to postmenopausal women and include:
Anastrozole (Arimidex)
Letrozole (Femara)
Exemestane (Aromasin)
All are taken as daily pills and have been shown to slow or stop the growth of estrogen-sensitive tumors.
Hormone Therapy Side Effects Can Mimic Menopause
As Munn hinted at, hormone therapy comes with side effects, and one of them can mimic menopause.
Depending on the endocrine or hormone medication, each one may have its own side effects. Typical side effects for certain types of hormone therapy drugs may include:
Bone pain
Joint pain
Loss of appetite
Nausea and/or vomiting
Fatigue
Constipation
What To Ask Your Doctor
If you have been diagnosed with breast cancer, you may have questions about keeping your strength through treatment. Here are a few questions to help you begin the conversation with your doctor:
What treatment will I be receiving?
What side effects are associated with this treatment?
Are there steps I can take daily to help minimize these side effects?
What physical activity routine do you recommend for me during treatment?
Do you have recommendations for someone who doesn’t particularly enjoy exercise?
Can you recommend a dietician who can help me with healthy eating tips and weight maintenance?
I’ve been having trouble sleeping. Do you have any treatment recommendations?
