# Does Menopausal Hormone Therapy Cause Breast Cancer? How Big Is the Real Risk? > Hormone therapy and breast cancer: who is at risk, how much and with which treatment? Duration of use, type of progestogen, women without a womb and a… Published: 21 October 2026 · Medically reviewed by: Op. Dr. Murat Alpay **Hormone therapy and breast cancer: who is at risk, how much and with which treatment? Duration of use, type of progestogen, women without a womb and a history of breast cancer.** "If I take hormone therapy, will I get breast cancer?" This is one of the questions menopausal patients ask most often, and one of those that most often puts them off starting treatment. The answer is not as simple as "yes" or "no": the risk changes with **the type of hormone therapy, how long it is used and a person's own risk factors**. In this article, based on international menopause guidelines and large studies, we explain with numbers how big the real risk is. For hormone therapy as a whole, see our page on [menopause treatment](https://www.muratalpay.com.tr/en/tedaviler/menopoz-tedavisi/); for general questions on safety, see our article on [whether hormone therapy is safe](https://www.muratalpay.com.tr/en/blog/menopozda-hormon-tedavisi-hrt-guvenli-mi-yanlis-bilinen-gercekler/). ## What Did the Large Study Show? The most frequently cited data on this subject come from the large **Women's Health Initiative (WHI)** study in the United States. The study was run in two separate arms, and the results are not the same: - **Oestrogen and progestogen together (combined therapy):** In women who still have a womb, with the synthetic progestogen added to oestrogen to protect the lining of the womb, a **slight rise** in breast cancer risk was seen. - **Oestrogen alone:** In women who had had the womb removed, no rise in breast cancer risk was found with oestrogen alone; in long-term follow-up, some analyses reported lower risk and fewer breast cancer deaths. Related treatment page [Body-Identical Hormone Therapy](https://www.muratalpay.com.tr/en/tedaviler/biyoesdeger-hormon-tedavisi/) Body-identical hormones are hormones with a chemical structure similar to those the ovaries produce. [Details →](https://www.muratalpay.com.tr/en/tedaviler/biyoesdeger-hormon-tedavisi/) ## How Big Is the Risk in Numbers? "Slight rise" may sound frightening; let us turn it into numbers. According to WHI data, when 10,000 women were followed for one year: - About **38** breast cancers were seen in the group taking combined hormone therapy. - About **30** breast cancers were seen in the group taking placebo (a dummy treatment). So the difference is about **8 extra cases** per 10,000 women per year. The World Health Organization and medical guidelines describe a rise of this size as "rare." ### Comparison with other everyday risk factors The relative rise in risk with combined therapy is about 1.2 to 1.3 times. Guidelines give these values for other risk factors: - **Severe excess weight** (body mass index above 35): about 2 times - **1-2 glasses of alcohol a day:** about 1.5-2 times - **An inactive lifestyle, or a first birth after age 30:** about 1.9 times This comparison shows that the effect of short-term hormone therapy is smaller than the risk that comes with these habits and situations. That is why, when thinking about hormone therapy, **modifiable risk factors** such as alcohol, weight and activity also need to be discussed. ## The Length of Use Matters - In the **first 3-5 years** of treatment, no marked rise in breast cancer risk is seen, or it is very small. - The risk begins to show mainly with **long-term** use of combined therapy, **beyond 5 years** and up to 10 years. - **After stopping** treatment, the risk falls over time and over the years approaches that of women who never used it; in long-term users, a slight trace may remain for a while. That is why the length and need for treatment are reviewed with the doctor every year. For information on how long hormone therapy is used, see our menopause treatment page. ## What Matters Most: the Type of Progestogen and the Route Guidelines state that the rise in risk comes mainly not from oestrogen but from the **synthetic progestogens added to combined therapy**. Synthetic progestogens can stimulate cell growth in breast tissue. - In large observational studies, combined treatments using **progesterone that resembles what the body makes (micronised progesterone)**, or some similarly structured progestogens, have been reported to show a more neutral profile for the breast. - Taking oestrogen **through the skin** (patch, gel) bypasses the first pass through the liver, so it does not stimulate clotting and does not raise the risk of venous clots or stroke. Skin oestrogen together with natural progesterone is counted among the regimens preferred for safety in current guidelines. We covered this in more detail in our article on [bioidentical hormone therapy](https://www.muratalpay.com.tr/en/blog/biyoesdeger-hormon-tedavisi-nedir-kimlere-uygulanir-antalya/). ## Women Who Have Had the Womb Removed In women who have had the womb removed (hysterectomy), there is no longer a risk of cancer of the lining of the womb, so there is no need to add a progestogen; oestrogen alone is given. In the WHI study and in other long-term follow-up studies, the risk of breast cancer did not rise in these women taking oestrogen alone. ## Hormone Therapy After Breast Cancer In women who have had breast cancer, **systemic (whole-body) hormone therapy is not recommended** because of the risk of the disease coming back. There are hormone-free options for these women: - **For hot flushes and night sweats:** Some non-hormonal prescription medicines and cognitive behavioural therapy (talking therapy aimed at reducing the distress) - **For vaginal dryness and painful intercourse:** Hormone-free moisturisers, lubricants and some device-assisted methods For these options, see our article on [vaginal dryness](https://www.muratalpay.com.tr/en/blog/vajinal-kuruluk-neden-olur-belirtileri-ve-guncel-tedavi-yontemleri/). ## What Is Done Before Starting Treatment? Before starting hormone therapy, your doctor assesses your personal risk: - A detailed **breast examination** and assessment of a current **mammogram** (breast X-ray) - A personal breast cancer risk score - **Breast density:** High breast density is an independent risk factor, and hormone therapy can temporarily increase density on a mammogram. - **Family history and inherited risk factors** such as BRCA. For early menopause symptoms in BRCA carriers who have had no cancer but have had the ovaries removed as a preventive step, short-term hormone therapy up to the natural age of menopause, after individual assessment, is considered safe. ## Is Vaginal Oestrogen (Local Treatment) a Risk for the Breast? Low-dose vaginal oestrogen (cream, tablet or ring) used for vaginal dryness and urinary complaints **acts locally** and does not raise the blood oestrogen level above menopausal levels. There is no evidence that it raises breast cancer risk in the general population. In women with a history of breast cancer, the first choice is always hormone-free products; in selected patients with severe symptoms, use can be considered only as a shared decision with the oncologist (cancer doctor). For details, see our article on [genitourinary syndrome of menopause](https://www.muratalpay.com.tr/en/blog/genitouriner-menopoz-sendromu-gsm-nedir/). ## Common Misconceptions - **"Every woman who takes hormone therapy gets breast cancer."** Wrong. The rise in risk is small (about 8 extra cases per 10,000 women per year) and shows mainly with use of more than 5 years of combined therapy containing a synthetic progestogen. - **"Oestrogen is the main cause of breast cancer."** Incomplete. In women who have had the womb removed, no rise in risk was found with oestrogen alone; the type of progestogen added is what matters for the rise. - **"A natural product is automatically safe."** The evidence on the effect and safety of herbal products is limited; serious interactions and liver damage have been reported for some of them. ## When Should You See a Doctor? - When you notice a new lump, hardness or thickening of tissue in the breast or armpit - When pulling in, dimpling or redness of the breast skin, or turning in of the nipple or bloody discharge develops - When there is unexpected vaginal bleeding or spotting in the menopause or while taking hormone therapy - When it is time for the yearly breast examination and mammogram ## Frequently Asked Questions ### If my breast cancer risk is high, can I take hormone therapy? This decision is individual. A family history of breast cancer is not on its own an absolute barrier to hormone therapy; but your doctor assesses it together with your risk score, breast density and mammogram results. Systemic hormone therapy is not recommended in women who have had breast cancer. ### If I stop hormone therapy, does the risk go away at once? No, but it falls over time. After treatment is stopped, the raised risk falls gradually and over the years approaches that of women who never used it. ### How often are check-ups needed during hormone therapy? Usually once a year; a breast examination, a mammogram and a review of whether treatment should continue are recommended. The decision varies from person to person. Written and reviewed by **Op. Dr. Murat Alpay** Specialist in Obstetrics and Gynaecology · Istanbul University, Istanbul Faculty of Medicine (Çapa) [Full biography →](https://www.muratalpay.com.tr/en/hakkinda/) [← All posts](https://www.muratalpay.com.tr/en/blog/) --- Original page: https://www.muratalpay.com.tr/en/blog/hormon-tedavisi-meme-kanseri-yapar-mi-gercek-risk-ne-kadar/ Last updated: 2026-10-21 Op. Dr. Murat Alpay — Specialist in Obstetrics and Gynaecology Op. Dr. Murat Alpay Practice, Tekelioğlu Cd. No:51 B Kat:2, Filo Apt., 07160 Muratpaşa / Antalya 0505 351 77 88 · Monday – Saturday 09:00 – 18:00 · Closed on Sunday *This information is for general guidance only and does not replace examination, diagnosis or treatment.*