For many years, breast cancer survivors experiencing menopause were advised to avoid hormone therapy entirely. However, emerging research and a forthcoming expert consensus paper for 2025 indicate there may be safe alternatives to consider.
Dr. Jenn Simmons, an integrative oncologist and breast surgeon based in Philadelphia, states, “The data continually points to hormones being safe after breast cancer. And the thing that we are repeatedly missing is why the opposite message was ever put out there, why it has remained out there, and why it is so pervasive.”
Challenging Traditional Wisdom
The prevailing treatment guidelines from key organizations, including the National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO), discourage systemic hormone therapy for hormone-positive breast cancer, which represents 70% to 80% of breast cancer cases. This caution stems from concerns that estrogen could promote the development or recurrence of breast cancer.
This approach gained traction following the controversial findings from the Women’s Health Initiative (WHI) released in 2002, which popularized the belief that estrogen increases the risks of breast cancer, heart disease, and stroke. Critics argue that the interpretation of WHI findings exaggerated the actual breast cancer risk associated with hormone therapy. According to the WHI, women using combined estrogen-progestin therapy had a relative risk increase of 26% for breast cancer compared to those on a placebo. This translated to a statistical increase from three to four cases per 1,000 women per year—an increment that shaped today’s treatment landscape.
Consequently, access to menopause care significantly declined for women in general, and especially for breast cancer survivors. Notably, further analysis has revealed that many of the initial WHI findings have been revised, showing age at therapy initiation as a variable in cardiovascular risk and that estrogen alone could potentially reduce breast cancer incidence and mortality.
Dr. Avrum Bluming, a key figure in the discourse surrounding this issue, highlights the challenges faced by breast cancer survivors. Following his wife’s distressing menopause symptoms post-treatment at age 48, he devoted his career to clarifying the safety of estrogen. He argues, “Depriving women of hormones for treatment of symptoms after breast cancer is not science-based.”
In a comprehensive review conducted in 2022, Bluming analyzed 26 different studies on hormone therapy for breast cancer survivors and found only one study indicating an increased local recurrence risk. This study, known as Sweden’s HABITS trial, was criticized for not including baseline mammograms, which could mean pre-existing conditions went unrecognized. Bluming asserts, “If 25 studies say one thing, and one study that is designed in a faulty way says another, you have to challenge what is being accepted as common wisdom now.”
Emerging Evidence and New Perspectives
Estrogen’s reputation received a boost in 2023 when Dr. Ann H. Partridge, of the Dana-Farber Cancer Institute, studied 516 women under 42 receiving anti-estrogen therapy. She discovered that allowing these women to pause their medication during pregnancy, which naturally elevates estrogen levels, did not lead to increased recurrence rates after seven years.
Fast-forward to 2025: Dr. Jaeyeon Kim from Indiana University published a synthesis of evidence suggesting that progesterone, not estrogen, primarily drives breast cancer risks. He explains, “Progesterone is the more important factor for development, progression, growth, and even recurrence of breast cancer. Estrogen not only doesn’t increase breast cancer risk, but it seems to decrease breast cancer risk—as long as progesterone or any progestin is not involved.”
Kim’s work, published in the *Annals of Oncology*, presents a potentially transformative approach to hormone therapy protocols, suggesting an individual assessment emphasizing estrogen with minimal progestin use for breast cancer survivors. He advises caution: while estrogen appears safe, it may need to be regulated carefully alongside progesterone, particularly for women retaining their uterus.
Adjusting Treatment Guidelines
In September 2025, an interdisciplinary team released the inaugural comprehensive Expert Consensus Statement on this topic, suggesting that hormone therapy should not be categorically deemed off-limits but should be tailored to individual patients in consultation with their healthcare teams. The consensus aims to align treatment plans with patient symptoms and risks of recurrence, recognizing the need for adaptable approaches rather than a one-size-fits-all mandate.
Increasing Acceptance Among Healthcare Providers
This evolving perspective is gaining traction among some oncologists who are already prescribing hormone therapy to breast cancer survivors. A poll of 77 oncologists conducted in 2024 revealed that 15% of their patients were undergoing hormone therapy. Dr. Holly J. Pederson, formerly of the Cleveland Clinic’s Breast Center, emphasizes the challenge in providing concrete recommendations amid evolving evidence.
The Broader Impact of Denying Hormone Therapy
The fear of recurrence from breast cancer often overshadows other health risks that arise during menopause. Dr. Pederson points out, “Most women who have breast cancer don’t die from breast cancer. They’re more likely to die from cardiovascular disease or stroke.” Recent studies highlight the cardiovascular risks associated with common breast cancer treatments, suggesting a complex interplay where the treatment may jeopardize heart health more than the cancer itself.
Menopause symptoms are another significant concern, as they can diminish quality of life for breast cancer survivors. According to a 2025 report by the Stanford Institute, women with menopause symptoms see diminished productivity, costing approximately $1.8 billion annually.
Ultimately, while not every survivor will choose hormone therapy, Dr. Bluming emphasizes the necessity of informed decision-making. He encourages survivors to engage in discussions with their medical teams regarding their specific risks of recurrence—both with and without intervention. With more nuanced understanding and ongoing research, it is crucial to acknowledge the potential benefits and to continue evolving treatment paradigms for breast cancer survivors.
