Olivia Munn shares brave breast cancer battle.
The actress was diagnosed with luminal B breast cancer — an aggressive and fast-moving form — in 2023. Since then, she has openly shared her difficult but inspiring health journey, offering updates, strength, and hope to others facing similar battles.
Olivia Munn’s journey with breast cancer has been one of strength, vulnerability, and quiet resilience. In 2023, the actress received a diagnosis that changed her life overnight — luminal B cancer, a fast-growing and aggressive form of breast cancer. But instead of sharing the news immediately, she chose a different path: she kept the diagnosis private for a full year. In March 2024, she finally opened up to the world through an emotional Instagram letter, revealing not just the medical details of her diagnosis and surgeries, but also the deeply personal reasons behind her silence.
Since going public, the former The Newsroom star has continued updating fans, using her experience to raise awareness about the type of cancer she faced. Luminal B breast cancer is one of the most common cancers affecting women in the United States — excluding skin cancers — and her goal has been to help other women understand the importance of early detection and risk assessment.
Olivia Munn’s Breast Cancer Diagnosis
Olivia detailed the beginning of her cancer discovery with striking clarity. her open letter. Surprisingly, the test did not show any known cancer-related mutations. But two months later, her world shifted.
Chose to appear publicly only on her “good days,” the days when she had enough strength to get dressed or take her young son to the park. Everything else — the fear, the exhaustion, the recovery, the pain medication, the vulnerability — she kept private, tucked away from the spotlight.
On March 13, 2024, she expanded further on how her cancer was detected. Olivia explained that during a routine visit, her OBGYN, Dr. Thais Aliabadi, decided to calculate her breast cancer risk assessment score, even though no alarming signs were present at the time. “The fact that she did saved my life.”
That risk assessment looked beyond genetics — it included her family history, age, and the fact that she had given birth to her son after age 30. All of these factors combined to place her at a 37% lifetime risk of developing breast cancer. That number changed everything. It triggered a chain of screenings: first an MRI, then an ultrasound, and finally a biopsy.
The biopsy results confirmed luminal B cancer in both breasts. Luminal B is known for being fast-moving and aggressive, requiring swift medical action. “Thirty days after that biopsy, I had a double mastectomy,” Olivia shared.
Why She Chose to Stay Silent
Olivia explained that one of the biggest reasons she kept her diagnosis private for so long was because she needed space — space to process, to heal, and to face the hardest parts of treatment without public scrutiny. “I needed to catch my breath and get through some of the hardest parts before sharing,” she said.
She emphasized that she feels incredibly fortunate to have caught the cancer early enough to still have options. “I’m lucky,” she wrote. “I want the same for any woman who might have to face this one day.”
Her message wasn’t just a recounting of her journey — it was a plea to other women to advocate for themselves, to keep up with regular screenings, and to ask their doctors about risk-assessment tools that could detect hidden cancer risks.
What Is Luminal B Breast Cancer?
According to information from City of Hope’s cancercenter.com, luminal B breast cancer expresses estrogen or progesterone receptors — or both — but does not express HER2 proteins. This type tends to grow faster and may be more aggressive than luminal A cancers. Because luminal B tumors can develop quickly, risk assessment, imaging, and timely follow-up appointments play a crucial role in catching them early.
Olivia’s story highlights exactly how essential these tools can be.
Life Beyond the Diagnosis
Even as she navigates treatment and recovery, Olivia has continued pouring love and energy into her family life. She and her husband, comedian John Mulaney, have been raising their two young children together while balancing medical appointments and long recovery days.
The couple welcomed their son, Malcolm Hiệp Mulaney, in November 2021, a bright spot long before cancer entered their lives. Their family grew again in September 2024, when they welcomed their daughter, Méi June Mulaney, via surrogate. Through every update Olivia has shared, it’s clear that her children and partner have been her anchors throughout one of the most challenging chapters of her life.
Her openness has resonated deeply with fans, many of whom have reached out to thank her for shining light on a cancer type they knew little about. By sharing both her vulnerability and her strength, Olivia has not only raised awareness but offered comfort to countless individuals walking similar paths.
From navigating multiple surgeries to balancing motherhood and recovery, Olivia Munn’s story is one of courage — the kind that grows quietly but shines powerfully when finally shared with the world.