Hormone Therapy and Breast Cancer - Is it a Risk? | Stella
14 mins

HT, breast cancer, and your family history

byDr. Nick Morse

Breast cancer is a common but often treatable form of cancer. Scientists used to think hormone therapy (HT) increased breast cancer risk for everyone, but this research is viewed differently now. What does this mean if you want to take HT and have a family history of the disease? What can lower your risk? Read our guide to HT and breast cancer for the answers to all these questions and more.

Breast cancer basics

Cancer is caused by the uncontrolled and invasive growth of cells leading to a tumor, which may then go on to spread – or metastasize – around your body. Breast cancer starts in your breast tissue. 

One in eight women in the US get breast cancer in their lifetime, and your risk increases as you age. Men can get breast cancer too, but it is far less common.

Breast cancer is a serious illness but treatments are improving all the time. It can be treated especially well when it is caught early in stage one or two. More than 90% of people who find breast cancer early can expect to live five years or more.

The stage of a cancer depends on the size of the original tumor and whether there is evidence that it has spread. This ranges from stage one (no spread) to stage four. Stage four means widespread cancer, with spread to areas like the lungs, bones, or liver.

What are the risk factors for breast cancer?

Certain things can increase your risk of breast cancer, such as:

  • Your weight – a Body Mass Index (BMI) over 25 puts you at a higher risk of breast cancer
  • How much alcohol you drink – more than one drink a day appears to increase your risk of breast cancer
  • Some forms of HT depending on your age
  • If you take oral contraceptive pills before age 35 – there appears to be a very small increase in your risk of breast cancer

What does this mean for you? You can lower your breast cancer risk by reducing how much alcohol you drink and managing your weight.

There are other risk factors that you can’t do anything about, such as:

  • Your family history
  • Your age
  • Your age when your periods began
  • Your age at menopause
  • Having dense breast tissue or breast lumps that are not cancerous, also known as fibrocystic breasts

A breast cancer risk calculator can give you an idea of your personal risk of breast cancer.

Does HT increase your risk of breast cancer?

You may have heard that HT is linked to increased breast cancer risk. Research in the 1990s and early 2000s led to many doctors recommending that most women should not take combined HT – estrogen and progesterone. However, scientists look at that research differently today. 

Doctors and scientists now agree that the research overestimated the risks of combined HT because they studied older women above the age of 60, who naturally have a higher risk of breast cancer, alongside younger women.  

Since then, further research has examined the risks of combined HT in more detail and shown a lower risk than previously thought for women between the ages of 45 and 60 and within 10 years after their last menstrual period. Newer HT formulations also seem to have lower risks than those in earlier studies.

However, the risk hasn’t disappeared. HT probably does increase your risk of breast cancer in some cases and the risk increases the longer you take it. Despite this, the risks are small when compared with other risk factors. For example, being overweight or drinking more than one drink per day appears to increase your risk by as much or more than taking combined HT. 

Let’s look at some of the different types of HT and their risks.

Combined HT – estrogen and progesterone

Current research suggests that 23 out of 1,000 women aged 50-59 with an average risk of breast cancer will develop the disease over five years. This is called the baseline risk.

If a similar group of 1,000 women take combined HT – estrogen and progesterone – for five years, 27 of them will develop breast cancer. This is equivalent to approximately one additional case of breast cancer per year compared to baseline.  

So how does this compare to lifestyle-based risk? 

  • Alcohol – Compared with women who do not drink, we would expect approximately one additional case of breast cancer per year in a group of 1,000 women who drink more than one drink per day
  • Overweight – We would expect five extra cases per year above baseline in a group of 1,000 women with a BMI over 25

Estrogen-only HT

In the original study, estrogen-only HT decreased the risk of breast cancer. Current figures suggest 19 cases of breast cancer per 1,000 women over five years. This is four fewer cases over five years than the baseline risk.

Keep in mind that you can only safely take estrogen alone if your uterus has been removed. Otherwise, progesterone is required to prevent endometrial cancer.  

Your risk

Think about your overall health if you are concerned about your risk of breast cancer with HT. You might be uncomfortable with the extra risk of combined HT if you are at higher risk of breast cancer already and your symptoms are mild. Others think the small increased risk is reasonable if taking HT treats menopause symptoms that disrupt daily life. 

You may be interested to know that combined hormone therapy taken when aged 45-60 actually lowers your overall risk of dying. This is mainly because there is a much lower risk of death associated with hip fractures and colon cancer, which outweighs any small increase in your risk of breast cancer and blood clots.  

Your risk after you stop taking HT

Your increased risk of breast cancer from taking HT gradually gets lower after you stop taking it.   

Can you take HT if you have a family history of breast cancer?

HT may still be suitable if you have a family history of breast cancer, but this is complex and you need to speak to a specialist doctor for advice. 

There are non-hormonal medication options that can be effective for treating hot flashes and night sweats if HT is not for you. These include gabapentin, some antidepressant medications, and a new medication called Veoza or fezolinetant.

Lifestyle changes are key to controlling many menopause symptoms, such as:

  • Managing your weight
  • Increasing your exercise levels
  • Improving your sleep quality and quantity

We share more about these later.

Can you take HT if you’ve had breast cancer before?

You should usually avoid combined HT if you’ve had breast cancer in the past, but there may be rare circumstances when it is still a reasonable option. Speak to a specialist in cancer survivorship care for advice if you have a history of breast cancer and are struggling with menopause symptoms.

Can you take HT if you have other breast cancer risk factors?

You can take combined HT if you have risk factors for breast cancer. But you will only get a prescription if the possible benefits outweigh the possible risks. See your healthcare provider for advice.

Read more about the benefits and risks of HT

How can you treat your menopause symptoms if you can’t have HT?

There are many non-hormonal treatments for menopause symptoms that have been proven to work.

Hot flashes

Non-hormonal medications that can help some menopausal symptoms including hot flashes include:

  • SSRI antidepressants, such as sertraline, citalopram, or fluoxetine
  • Clonidine
  • Gabapentin
  • Veoza or fezolinetant

Bladder and vaginal problems

If you are struggling with urinary or vaginal symptoms of menopause, non-hormonal options are available and include:

  • Vaginal moisturizers. These are widely available to help vaginal dryness or painful sex
  • Lubricants. Try a pH-balanced lubricant to relieve painful sex

Vaginal estrogen is the most effective treatment for urinary frequency, vaginal dryness, and painful sex. Vaginal estrogens are generally safe to use regardless of your medical history or age – even if combined HT is too risky for you. Vaginal tablets, creams, gels, and pessaries are all safe and effective.

Other symptoms

Many lifestyle changes are proven to help with menopause symptoms, including hot flashes, sleep issues, anxiety, and low mood. Try to:

  • Get enough exercise
  • Maintain a healthy weight
  • Eat a nutritious diet
  • Rethink your caffeine, alcohol, and nicotine intake

Don’t be overwhelmed by this list! Start small. Little changes can make a big difference. For ideas on how to increase how much you move, read our blog on the best exercise for menopause.

What should you do if you are on HT and develop breast cancer?

Current guidance advises stopping combined HT immediately if you are diagnosed with breast cancer. This is because some cancers are affected by hormones, and may even grow more quickly when estrogen or progesterone is present. These are known as hormone-dependent tumors.

Speak to your healthcare provider as soon as possible if you are on HT and find any breast changes – just as you would normally.

How to check your breasts

Checking your breasts and chest regularly may help you pick up on any changes or lumps. Once a month is a good guide. 

Avoid checking them when you are on your period – if you still have periods.

The shower or bath is a common place to do this, as soap makes it easier to run your hands over your breasts. Make sure to:

  • Feel your chest, both breasts and armpits. You are looking for any changes. This includes lumps, thickenings, sore areas, or changes in texture
  • Look at your breasts in the mirror. Look out for any rashes, dimples, puckering, and changes to size or shape.

Sometimes changes are obvious, but other times you may be unsure – you should always consult your healthcare provider if you have any questions.


Breast screenings help find breast cancer early. At a breast screening you will have a mammogram, which is an X-ray picture of your breasts.

Epidemiologists, doctors, and medical professional organizations disagree on the exact recommendations for breast cancer screening. But most experts recommend that people at average risk – with no strong family history or strong personal risk factors – should:

  • Start mammograms between age 40 and age 45
  • Repeat mammograms every one to two years
  • Stop mammograms after age 74

Early screening

If you or your healthcare provider, such as PCP or OBGYN, are concerned that you have an increased risk of breast cancer, you should speak with them to get a detailed risk assessment.  

Your recommendations for breast screening may change if you are found to be at higher-than-average risk. You may be referred for a breast MRI in addition to your mammogram. 

Final word

Combined HT can contribute to the risk of breast cancer but this risk is small and doesn’t outweigh the potential benefits for most people. It is important to discuss your menopause treatment with your healthcare provider, especially if you have had breast cancer, have a family history, or are at higher risk for another reason. Arrange an appointment to review your treatment if any of these circumstances have changed recently.

And don’t forget to pop your next breast screening in your calendar. This is one piece of self-care that you shouldn’t skip or put off!

Find out more about menopause on our blog or in our symptoms library.