Hormones, Cancer, and the Path That Fits You
An honest look at bio-identical hormone replacement, the evidence, and the conversation that should happen before any prescription is written.
A patient sat across from me last spring, hands folded in her lap, exhausted from a third sleepless night in a row. The hot flashes had become unrelenting. Her mood had quietly fractured. Her libido was a memory. And the question she came in with was the same one I hear at least once a week… “Will hormone replacement give me cancer?”
It’s a fair question. It’s also a question that doesn’t have a clean yes or no answer… and I think the honest physician owes their patient more than a soundbite either way.
So let me try to give you the long version. The one I would give to a friend.
Where I Come From On This
I personally prescribe bio-identical hormone therapy in my practice. I want to be clear about that up front, because everything else I say here is shaped by that clinical experience. I was trained by Dr. Todd Cameron, who studied under Dr. Neil Rouzier, MD. Dr. Rouzier has been one of the pioneers of bio-identical hormone replacement since the early 1990s, and his evidence-based teaching through WorldLink Medical (the “Mastering the Protocols for Optimization of Hormone Replacement Therapy” series) has shaped how thousands of physicians approach this work. If you want to understand the philosophy and the literature base that runs through my own approach, his work is a wonderful place to start. His book Normal Isn’t Optimal lays it out plainly… the levels we call “normal” in lab ranges often reflect what is average for a population in decline, not what supports vibrant function across the lifespan.
That perspective informs my work. It does not, however, make me a true believer. I have seen patients flourish on bio-identical hormones, and I have also seen patients for whom replacement was not the right road. Vis Medicatrix Naturae… the healing power of nature… reminds me that the body is more often a partner than a problem to override.
What The Evidence Actually Shows
The headline most people remember is this: hormone replacement therapy causes breast cancer. That headline came largely from the Women’s Health Initiative trial in the early 2000s, and it changed clinical practice almost overnight. The story, as it has turned out, is more textured than the headline made it sound.
A recent comprehensive review in Annals of Oncology by Kim and Munster (2024) helps clarify the landscape, and so does the long retrospective from Chlebowski and Aragaki (2023), who were both involved in the original WHI work. Here is the more honest picture that has emerged from the past two decades of research…
Estrogen-only therapy in women who have had a hysterectomy shows little increase, and sometimes a reduction, in breast cancer risk (Chlebowski & Aragaki, 2023; Kim & Munster, 2024). This is the opposite of what most people assume.
Combined estrogen-progestin therapy using synthetic progestins like medroxyprogesterone acetate does consistently increase breast cancer incidence, and the effect can persist for years after stopping (Kim & Munster, 2024; Wu et al., 2026). This is the elevated risk that the original WHI study identified… and that public conversation then generalized to all hormone replacement.
The progestin distinction matters enormously. A systematic review and meta-analysis by Asi and colleagues (2016) found that natural micronized progesterone appears to carry a different risk profile than synthetic progestins. Gompel and Plu-Bureau (2018) reached similar conclusions reviewing the literature on progesterone, progestins, and the breast in menopause treatment. This is one of the central reasons I lean toward bio-identical formulations in my practice… the molecule the body recognizes appears to behave differently in tissue than the molecule pharmaceutical chemistry created as a patentable substitute.
Hormonal contraceptives (both combined and progestin-only) confer a small but statistically significant short-term increase in breast cancer risk (Fitzpatrick et al., 2023; Mørch et al., 2017). The absolute excess remains modest, but it is real, and it deserves an honest conversation with patients of reproductive age.
Endogenous hormones (your own circulating estrogen, testosterone, and progesterone) also matter. Higher postmenopausal estrogen and testosterone levels have been associated with increased breast cancer risk in prospective studies and Mendelian randomization analyses (Hankinson et al., 2007; Missmer et al., 2004; Nounu et al., 2022). The role of endogenous progesterone is genuinely less clear, with some evidence suggesting it contributes to risk through menstrual cycle proliferation (Bennink et al., 2023) and other evidence remaining inconclusive (Trabert et al., 2020).
It is worth mentioning that some clinicians and researchers, including Bluming, Hodis, and Langer (2023), have published thoughtful critiques of how the WHI data has been interpreted, arguing that the absolute risk numbers do not justify the blanket fear that took hold in the public mind. I find their perspective useful in keeping me from either overstating or understating what the data actually says. Like most things in clinical medicine, the truth lives somewhere between the loudest voices on either side.
Why I Start Gentler When I Can
Just as a tree leans into the sun before it reaches deeper for water, the body often offers gentler paths before it asks for the more intensive interventions. Many of my patients moving through perimenopause and menopause do beautifully with botanical and lifestyle support alone, especially in the early years of the transition.
Some of the herbs I consider when co-creating a starting protocol include black cohosh for vasomotor symptoms, vitex (chasteberry) for cycle support in the earlier perimenopausal years, maca for libido and steady energy, ashwagandha and rhodiola for adrenal resilience, and sage for hot flashes. Phytoestrogen-containing foods such as organic fermented soy, ground flaxseed, and red clover can play a supportive role for some women as well. None of these are pharmaceutical sledgehammers… they are gentle nudges to a system already trying to find balance.
Alongside the botanicals, the lifestyle foundation matters more than most people realize. Quality sleep, daily movement, protein-forward nutrition, stress modulation, sunlight, and community… these are not soft recommendations. They are the soil. Without them, no hormone protocol (synthetic, bio-identical, or otherwise) will deliver the results my patients are hoping for.
If we have given the gentler approaches an honest try and the symptoms are still meaningfully diminishing quality of life, then bio-identical replacement enters the conversation as one option among several, with eyes wide open.
Co-Creating The Path
Healing, in my experience, is rarely a protocol I hand down from on high. It is a co-created process. I bring the literature, the clinical pattern recognition, and the physiology. The patient brings her values, her history, her body’s response over time, and her own intuitions about what feels right. When those two streams meet honestly, good medicine tends to emerge.
For one woman, bio-identical estradiol with cyclical or continuous bio-identical progesterone is the path that lets her sleep, think clearly, and reclaim intimacy with her partner. For another, herbal support and lifestyle is more than enough. For a third, the conversation circles back two years later when the perimenopause symptoms shift. The right answer is the one that fits this person in this season of her life.
This is also why working with a physician who genuinely understands these things matters so much. Hormone replacement is not a one-size-fits-all prescription. It requires careful baseline labs (often including estradiol, progesterone, testosterone, DHEA-S, SHBG, thyroid panel, and metabolic markers), thoughtful dosing, attention to delivery route (transdermal, oral, injectable, and pellets all behave differently), and ongoing monitoring. A practitioner trained in the Rouzier tradition, or any of the rigorous BHRT training pathways, will have the tools to optimize rather than guess. Please do not accept guessing from your provider when better is available.
The Clear “No” That I Hold
There is one place where my flexibility ends, and I want to be unambiguous about it.
I do not believe hormone replacement therapy is appropriate for anyone who has been diagnosed with a hormone-sensitive cancer, unless there is a clear and well-documented indication that the benefits will outweigh the risks. This includes ER+/PR+ breast cancer, certain endometrial cancers, certain ovarian cancers, and prostate cancer in men.
There are nuanced exceptions discussed in the literature. A 2024 Italian expert group consensus opinion from Cagnacci and colleagues offers careful guidance on systemic hormone therapy after breast and gynecological cancers, and Deli, Orosz, and Jakab (2019) published a useful review of HRT in cancer survivors more broadly. For BRCA mutation carriers, Huber and colleagues (2021) provide a systematic review of risks across ovarian, endometrial, and breast cancer that is worth reading. These are not blanket prohibitions in every case… they are conversations that require oncology input, careful risk-benefit analysis, and humility about how much we still do not know.
If you are a cancer survivor and someone is offering you hormone replacement without that depth of consideration, please get a second opinion. Yongue and colleagues (2026) recently published a narrative review on cancer risk with HRT that lays out the considerations well.
Closing Thoughts
Robert Frost wrote of two roads diverging in a yellow wood, and how the choosing of one shapes everything that follows. Hormone replacement is a road like that. It is one road among several, and not the right road for everyone… but for some women (and some men) it can be genuinely transformative. The bone density preserved. The sleep restored. The cognition that returns. The intimacy that comes back. These are not small things. Bollam, Karam, Shufelt, and Faubion (2026) recently published a thoughtful piece on balancing the risks and benefits of menopausal hormone therapy that I would recommend to anyone wrestling with this decision.
What I hope you take from this is a posture for the journey. Take the time to find a physician who knows the literature and is willing to walk with you through it. Try the gentler approaches first when it makes sense. Stay honest with yourself about what is working and what is not. Bring your whole self… physical, mental, emotional, energetic, and spiritual… into the conversation. And when in doubt, lean toward partnership over prescription.
The body has its own wisdom. Our work, as physicians, is to listen alongside it.
Warmly,
Dr. Michael Hummel, ND
References
Asi, N., Mohammed, K., Haydour, Q., Gionfriddo, M., Vargas, O., Prokop, L., Faubion, S., & Murad, M. (2016). Progesterone vs. synthetic progestins and the risk of breast cancer: a systematic review and meta-analysis. Systematic Reviews, 5. https://doi.org/10.1186/s13643-016-0294-5
Bennink, H., Schultz, I., Schmidt, M., Jordan, V., Briggs, P., Egberts, J., Gemzell‐Danielsson, K., Kiesel, L., Kluivers, K., Krijgh, J., Simoncini, T., Stanczyk, F., & Langer, R. (2023). Progesterone from ovulatory menstrual cycles is an important cause of breast cancer. Breast Cancer Research, 25. https://doi.org/10.1186/s13058-023-01661-0
Bluming, A., Hodis, H., & Langer, R. (2023). ‘Tis but a scratch: a critical review of the Women’s Health Initiative evidence associating menopausal hormone therapy with the risk of breast cancer. Menopause, 30, 1241–1245. https://doi.org/10.1097/gme.0000000000002267
Bollam, R., Karam, J., Shufelt, C., & Faubion, S. (2026). Menopausal hormone therapy and breast cancer: Balancing risks and benefits. Maturitas, 208, 108894. https://doi.org/10.1016/j.maturitas.2026.108894
Cagnacci, A., Villa, P., Grassi, G., Biglia, N., Gambacciani, M., Di Carlo, C., Nocera, F., Caruso, S., Becorpi, A., Lello, S., & Paoletti, A. (2024). Systemic hormone therapy after breast and gynecological cancers: an Italian expert group consensus opinion. Climacteric, 28, 4–14. https://doi.org/10.1080/13697137.2024.2418503
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Deli, T., Orosz, M., & Jakab, A. (2019). Hormone Replacement Therapy in Cancer Survivors – Review of the Literature. Pathology Oncology Research, 26, 63–78. https://doi.org/10.1007/s12253-018-00569-x
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Kim, J., & Munster, P. (2024). Estrogens and breast cancer. Annals of Oncology, 36, 134–148. https://doi.org/10.1016/j.annonc.2024.10.824
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Rouzier, N. (2023). Normal Isn’t Optimal: A Guide to Bioidentical Hormone Replacement Therapy. Neal Rouzier, MD.
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Wu, Q., Shen, L., Hu, S., Yang, R., Wang, Y., Xue, D., Sun, Y., & Dai, Z. (2026). Relationship between menopausal hormone therapy and incidence risk of breast cancer: systematic review and meta-analysis. Annals of Medicine, 58. https://doi.org/10.1080/07853890.2026.2640244
Yongue, G., Nash, Z., Talaulikar, V., & Nicum, S. (2026). Risk of Cancer With Hormone Replacement Therapy: A Narrative Review. BJOG: An International Journal of Obstetrics and Gynaecology. https://doi.org/10.1111/1471-0528.70176