Does Hormone Replacement Therapy Cause Cancer?

Dr. Rishi Verma, MDFeatured, Hormones

August 31, 2016  /  Featured, Hormones

I feel like I need to deviate from my regular weekly postings to comment on a recent study, which is attracting media world-wide.

On August 23, 2016, a study titled ‘Menopausal hormone therapy and breast cancer: what is the true size of the increased risk?’ was released. 1

The findings of the study

The researchers used questionnaires from participants in the UK generations study cohort to estimate a hazard ratio for breast cancer in post-menopausal women. They then compared the development in breast cancer to those who did and those who did not use hormone replacement therapy (HRT).

The data showed that if you used estrogen plus progestogen2 therapy for 5 years, your risk of breast cancer is 2.74x (as compared to non-users) and if you use the same therapy for 15 years, your risk moves to 3.27x.

Is this data surprising?

 In the medical world, this is really not surprising data. We already knew from the women’s health initiative3 that there is an increased risk of breast cancer when taking estrogen plus progestogen therapy. The reason this new study is gaining attention is because the risk is seemingly greater than previously known.

The devil is in the details

We have long known that synthetic hormones have a carcinogenic (cancer causing) effect.

When you look at the constitution of the most commonly prescribed hormones on the market, here is what you will find.


  • Contains 20+ estrogens
  • All estrogens are derived from pregnant horse urine
  • The majority of the estrogens are estrone (E1) compounds, which are unknown to the human body and unfavourable to our body chemistry
  • The pill is taken orally, which is a dangerous way to take estrogen, as it has been linked to blood clots


  • Synthetic progestogen which bears little resemblance to progesterone
  • Has a similar effect to progesterone in the uterus, but a directly opposite effect on all other body tissues
  • Is a known carcinogen
  • Is strong enough to cause osteoporosis in young women

When reading this list, it comes as no surprise that taking these compounds for 5-15 years will increase your risk of breast cancer.

Testing for hormone levels

Another important factor that is not being discussed is testing of hormones. Anyone who has been seen for hormone therapy at one of our clinics knows that they have a complete urine hormone test done at least once per year.

It is natural to think that such testing would be done on every single participant of a major medical study … wrong.

It baffles me to see that these so-called ‘scientific studies’ are not testing a single patient for hormone levels. They are simply giving the patients synthetic hormones (with known potential harm), and watching for rates of breast cancer as they go along.

If they did happen to test a patient on synthetic hormones with a urine hormone test, they would likely immediately stop the therapy. I have tested patients who came to me on synthetic hormones, and believe me that the results are shocking.

What should you do?

Navigating through the world of hormone decline and deciding whether to take HRT is a complex one. If you are considering HRT, please go through the following checklist to ensure your safety:

  • Only trust the judgement of a doctor who is well versed in the pros and cons of both synthetic and bio-identical hormones
  • If you choose to take hormones, you should test your levels with a 24 hour urine sample at least once per year, or as indicated by your physician
  • Do not use oral estrogens – they are strongly linked to blood clots
  • Do not take anything labelled as a progestogen – this is a synthetic version of progesterone, which bears very little similarity
  • Use the lowest dose possible to achieve your desirable effect
  • Ensure you are engaging in appropriate screening for breast and bone health, which your doctor can arrange

I hope this clears up any confusion you may have.

All the best in your health journey,

Dr. Rishi Verma, MD
Dr. Verma on linkedin

  1. Br J Cancer. 2016 Aug 23;115(5):607-15. doi: 10.1038/bjc.2016.231. Epub 2016 Jul 28.
  2. A progestogen is a synthetic version of the naturally occuring compound progesterone. Progestogens may also be referred to as progestins in the literature.
  3. JAMA. 2002;288:321-333.


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Dr. Rishi Verma, MD

Medical Director
Dr. Verma is one of Vancouver’s most regarded physicians in the field of integrative medicine. He is medical director of a group of six doctors, and is active in teaching doctors how to improve their delivery of health care. He also runs a busy integrative medicine practice with a dedicated group of clients.