Osteoporosis risk and hormone therapy
Osteoporosis is thinning of the bones so that they become more brittle. This increases the risk of breaking (fracture).
Our bones start to thin after the age of 35 or so, as part of the natural ageing process. But this is not usually noticeable. After the 
, the levels of the sex hormone oestrogen decrease. This causes bones to lose strength.
Men lose bone strength too, as they age. Because men don’t have a menopause, this is usually seen a bit later in life than women.
Hormone therapy and cancer
Some cancers use hormones to grow or develop. Doctors call these cancers hormone sensitive. Hormone therapy works by blocking or lowering the amount of these hormones. For people with breast or prostate cancer, hormone therapy is often an important part of treatment. Ovarian and womb cancer might also be hormone sensitive.
Hormone therapy can increase the risk of bone thinning.
Cancer treatment and bone thinning in women
Any cancer treatment in women that lowers oestrogen levels can increase the risk of osteoporosis. These treatments include:
- chemotherapy which causes an early menopause
- radiotherapy to the ovaries which stops them working
- surgery to remove the ovaries before your menopause
- hormone therapy drugs, such as
aromatase inhibitors or luteinising hormone releasing hormone agonists (LHRH agonists)
Breast cancer and hormone therapy
Hormone therapy is only likely to work if your breast cancer cells have oestrogen receptors (ER). 7 out of 10 breast cancers (70%) have oestrogen receptors. This is called oestrogen receptor positive cancer or ER positive cancer.
You might have hormone therapy if you have ER positive breast cancer:
- before surgery
- after surgery
- if you can’t have surgery
The hormone therapy drugs you might have include:
- tamoxifen
- aromatase inhibitors (AIs)
- luteinising hormone releasing hormone agonists (LHRH agonists)
Tamoxifen and the risk of bone loss
Before the menopause
Tamoxifen usually only reduces bone density by a small amount. In young women who have had treatment to stop the ovaries producing oestrogen (ovarian suppression) followed by aromatase inhibitor therapy, bone density can be lost more quickly. Treatment with tamoxifen for 2 to 5 years before having aromatase inhibitors may slow down the rate of bone loss.
After the menopause
Tamoxifen prevents bone loss in post menopausal women.
Aromatase inhibitors (AIs) and the risk of bone loss
Aromatase inhibitors are the main hormone treatment used for post menopausal women.
Aromatase inhibitors include:
Research has shown that all AIs can increase the risk of osteoporosis. There is some evidence that bone strength tends to recover when treatment has stopped.
Prostate cancer and hormone therapy
Prostate cancer usually depends on testosterone to grow. Hormone therapy blocks or lowers the amount of testosterone in the body.
You might have hormone therapy on its own or with:
- radiotherapy
- chemotherapy
The hormone therapy drugs you might have include:
- luteinising hormone releasing hormone agonists (LHRH agonists)
- anti androgen tablets
- a gonadotrophin releasing hormone (GnHR) blocker - this is called degarilex
Hormone therapy for prostate cancer and the risk of bone loss
LHRH agonists include:
Anti androgen tablets include:
- bicalutamide (Casodex)
- flutamide (Drogenil)
- enzalutamide (Xtandi)
- abiraterone (Zytiga)
- cyproterone acetate (Cyprostat)
- darolutamide (Nubeqa)
People with prostate cancer, who don’t have treatment, already have higher than usual rates of osteoporosis. And this increases further for people who have treatment with anti androgens. This means your risk of bone fracture is also higher.
Your medical team understand this risk. Keeping your bones as healthy as possible while on hormone treatment is part of your treatment plan.
Talking about your osteoporosis risk
Talk to the team looking after you if you are worried about bone thinning.
Breast cancer
Guidance from a UK expert group recommends that women taking hormone therapy for breast cancer, who are at high risk of osteoporosis, should have bone density measured at:
- the start of treatment
- regular points throughout treatment
The test used is called a dual energy x-ray absorptiometry scan (DEXA scan) of bone mineral density (BMD).
Prostate cancer
The National Institute for Health and Care Excellence (NICE) recommend that your team should look at your risk of fracture when you start hormone therapy. This might mean having a dual energy x-ray absorptiometry scan (DEXA scan) of bone mineral density (BMD).
You might also have your done density measured during your treatment.
How to help yourself
Exercise is important for bone health. It can also help you lower the risk of a fall that may result in fracture.
To have an effect on bone thinning, we know this has to be weight bearing exercise. Swimming doesn’t help, because your bones aren't supporting your weight.
It’s great if you already take part in sport. But many of us don’t take enough regular exercise. The best way to start to tackle this is to try and bring exercise into your daily life.
Tips:
- walking is good
- household activities can also help, such as cleaning, gardening, shopping or even going up and down stairs
- you could join an exercise group or class - it doesn’t have to be very energetic, gentle controlled exercise such as Tai Chi can be good
- although swimming doesn’t help, exercise classes that you take at the swimming pool (aqua aerobics) can, because of the resistance of the water.
The most important thing is that you get into the habit of exercise, however you choose to do it.
An average adult should have about 700 milligrams of calcium every day for good bone health.
Our main dietary source of calcium is dairy products. You’re unlikely to be short of calcium if you eat a normal, balanced diet including dairy foods. But not everyone eats dairy.
Main sources of calcium
You get the most calcium from milk, cheese and yoghurt. But if you don’t eat dairy foods, there is also calcium in:
- green vegetables, such as cabbage, broccoli and okra
- soya products, including tofu
- tinned fish where you eat the bones (sardines, salmon and pilchards)
- nuts
- dried fruit
- fortified breakfast cereals
- bread and other foods made from flour (all UK white flour is enriched with calcium and wholemeal flour contains it naturally)
Substitute milks, such as rice milk, oat milk and soya milk can also have added calcium. Check the label to find out how much they contain.
Other sources of calcium
There is calcium in tap water, but the amount varies depending on how hard the water is in your area. Some fruit juices and bottled waters have added calcium.
Calcium supplements
You could take supplements instead of calcium rich foods. Dieticians don’t recommend that you take more than the amount you should have in a normal diet. Too much calcium can be harmful.
The Department of Health and Social Care says that taking up to 1,500 milligrams a day is unlikely to do any harm.
Breast cancer
There’s no evidence to suggest that women with breast cancer need any extra calcium. But if you already have osteoporosis, more calcium could help - between 1,000 and 1,200 milligrams a day.
For your body to use calcium, you also need vitamin D. Your body needs sun to make vitamin D. There is vitamin D added to some fat spreads and breakfast cereals. It’s also found in oily fish and egg yolk.
Public Health England recommend that in winter and autumn, people in the UK should consider taking a daily supplement of vitamin D containing 10 micrograms. This is because it is difficult for people to get enough vitamin D through their diet.
The following people might not get enough vitamin D from sunlight in summer or winter. So they might need to consider taking a supplement all year round:
- people with dark skin from African, African-Caribbean and South Asian backgrounds
- people who cover their skin when outdoors
- people in care homes or institutions
You may want to ask your specialist or breast care nurse for a referral to a dietician at the hospital. A dietician can help you to work out whether you are getting enough calcium and vitamin D in your diet.
Staying safe in the sum
If you are out in the sun, remember to protect against skin cancer. The best way to enjoy the sun safely and protect your skin is to use a combination of shade, clothing and sunscreen.
Bone strengthening treatment
There are bone strengthening treatments available to prevent or slow down bone thinning.
The most common ones are:
- bisphosphonates - you have them as tablets or injections
- denosumab (Prolia, Xgeva) - as an injection just below the skin
Bisphosphonates are drugs that target areas of higher bone turnover. Denosumab is a type of targeted therapy called a monoclonal antibody.
Prostate cancer
You might have bisphosphonate treatment if you’re having hormone therapy and have osteoporosis. If you can’t have bisphosphonates for any reason you might have denosumab.
Breast cancer
You might have bisphosphonates if you have osteoporosis, or you are at a high risk of developing it.
Research and clinical trials
Researchers are interested in improving bone health for people having cancer treatment.
Scientists are looking at blood tests to measure substances that may show bone changes in people with prostate cancer. These are called CTx and P1NP.
A study team are looking at the bone health of women who took part in a clinical trial called the AZURE trial. This clinical trial was for women with breast cancer. They are now comparing those who did and didn’t have a bisphosphonate as part of their treatment. The main aims of this study are to:
- see if the bisphosphonate given in the AZURE trial has a positive effect on how strong and thick (dense) the bones are, and how long this lasts
- see how quickly the bone repairs and renews itself
You can find a clinical trial looking at bone thinning (osteoporosis) and cancer on our clinical trials database. Click on the ‘recruiting’, ‘closed’ and ‘results’ tabs to make sure you see all the trials.
More information about osteoporosis
The Royal Osteoporosis Society has a lot of information on the causes, prevention and treatment of osteoporosis.
They also have guidelines for doctors treating women with hormone therapy for breast cancer.
