About bone health and cancer

This information is about bone health. It is for people who are having, or have had cancer treatments that may affect their bones.

This information is not about bone cancer. We have separate information about bone cancer.

Bones are made from a protein called collagen. They are strengthened by calcium and other minerals. This makes bones strong and rigid but not heavy. Your bones:

  • provide support and protection for your internal organs – for example, the ribs protect the heart and lungs
  • work with your muscles so that your body can move
  • store calcium and other minerals
  • contain bone marrow, which is where blood cells are made. 

Types of bone

There are two types of bone:

  • Compact bone
    This is the hard, rigid shell on the outside of the bones.
  • Cancellous bone
    This is inside the compact bone. It is arranged like a honeycomb or mesh with lots of spaces. It is sometimes called spongy bone because the spaces look a bit like a sponge.


Bone and bone marrow
Image: The structure of a long bone


Bone growth and repair

Bones are living tissue. They have a blood and nerve supply to keep them healthy. Bones are constantly being renewed. This helps maintain their strength and shape.

Inside the bones, there are two types of bone cell:

  • Osteoclasts, which break down and remove old bone.
  • Osteoblasts, which build new bone.

Our bones stop growing longer by the time we are about 18 years old. But bones continue to increase in thickness (density) until our late-20s.

Bone density stays about the same into our mid-30s. After this, bone density slowly decreases. This is because osteoclasts remove more bone than osteoblasts make.

Cancer treatments and bone health

Cancer treatments that reduce the levels of the hormones oestrogen or testosterone can cause bone loss. This includes:

Hormonal therapy for breast cancer

Some drugs that treat breast cancer work by reducing oestrogen levels. They include anastrozole (Arimidex®), exemestane (Aromasin®), letrozole (Femara®) and goserelin (Zoladex®). Taking these drugs for several months or more can cause bone loss and increase the risk of fractures.

Not all hormonal therapies for breast cancer cause bone loss. The drug tamoxifen reduces bone loss in women who take it after the menopause.

Hormonal therapy for prostate cancer

Some drugs for prostate cancer reduce the level of testosterone. These drugs include goserelin (Zoladex®), leuprorelin (Prostap®) and triptorelin (Decapeptyl®, Gonapeptyl Depot®). A side effect of these drugs is bone loss.

Chemotherapy drugs

Some chemotherapy drugs affect the ovaries or testicles. This can reduce the levels of oestrogen in women or testosterone in men. The effect can be temporary or permanent. Having lower than normal levels of these hormones before the age of 50 can lead to bone loss. Your cancer doctor or nurse can tell you if chemotherapy is likely to affect your hormone levels.

A few chemotherapy drugs, such as methotrexate and ifosfamide, may weaken bones. If your treatment includes these drugs, your doctor or nurse will talk to you about this.


Hormone levels are reduced if:

  • a man has an operation to remove both his testicles
  • a woman has surgery to remove her ovaries before she has gone through the menopause.

The reduced hormone levels can lead to bone loss.

Radiotherapy to the ovaries

Radiotherapy to the ovaries before the menopause reduces oestrogen levels in women. This increases the risk of bone thinning (osteoporosis).

Radiotherapy to the pelvis

Radiotherapy can cause changes to the bone in the area being treated. It is most likely to happen when women are given radiotherapy to the pelvic area. This may be used to treat cancer of the anus, bladder, womb, cervix or rectum.

Radiotherapy can cause changes to the bone, meaning it cannot cope as well with the normal stresses put on it. This can lead to fractures. Doctors call these types of fractures pelvic insufficiency fractures (PIFs).

Steroid therapy

Some people have steroids as part of their cancer treatment. Commonly used steroids include prednisolone and dexamethasone. High-dose steroid treatment, or taking steroids for three months or more can cause bone loss and increase the risk of fractures.

Targeted therapies

Targeted therapies are drugs that target changes within cancer cells to stop them growing.

Some targeted therapy drugs may affect bone health. These drugs are imatinib, nilotinib and dasatinib. They may affect the level of calcium in the blood. If calcium levels are low for a long time, this can cause bone loss. It is important to get the recommended amount of calcium and vitamin D. Your cancer specialist will check your calcium levels with a blood test every 3 to 6 months. If your levels become lower than normal, they can give you treatment to correct this.

Other factors that affect bone health

There are other that factors that can affect your bone health and risk of osteoporosis.

  • Age

    Your bones are strongest when you are in your 20s. Bone loss begins in your 30s. The risk of a fracture because of bone loss increases from the age of 50. Fractures are most common over the age of 65 in women and over the age of 75 in men.

  • Low hormone levels

    Low levels of the hormones oestrogen or testosterone can affect bone density. Oestrogen levels naturally drop after the age of 50. Testosterone levels can also drop after the age of 50, but not as much as oestrogen. Some cancer treatments can lower oestrogen or testosterone levels and increase risk of bone loss. If these hormone levels are low, your doctors can talk to you about treatments to protect your bones.

  • Gender

    Anyone can develop osteoporosis, but it is more common in women. Before the menopause, the hormone oestrogen keeps women’s bones healthy. But after the menopause, oestrogen levels decrease and women lose bone density more quickly.

  • Physical activity

    Being physically active when you are a young adult helps make your bones stronger and denser. Doing regular exercise throughout your life helps to keep your bones strong. Weight-bearing exercises such as walking or climbing stairs are also good for bone strength.

  • Diet

    Eating a balanced diet helps keep bones healthy. It is important to get the recommended amounts of protein, calcium and vitamin D, to help build bones and keep them strong.

  • Family history of osteoporosis

    If one, or both, of your parents have had osteoporosis, you are more at risk of developing it. If you are worried about this, talk to your doctor.

  • Fragility fractures

    If you break a bone after falling from a standing height or less, this is called a fragility fracture. After the age of 50, it can be a sign that you have weaker bones and are more at risk of having a fracture in the future.

  • Weight

    People who have a low body weight are more at risk of fractures than people who are a healthy weight.

    Body mass index (BMI) is a measure of healthy weight. Your BMI is based on your height and weight. Guidelines recommend that for bone health and general health, your BMI should be between 19 and 25kg/m2. Your GP or practice nurse can work out your BMI for you.

    You can use the NHS BMI calculator to find your BMI. Speak to your GP or nurse if you are above or below the healthy range.

  • Smoking

    Research has shown that smoking reduces bone density, weakens bones and increases the risk of osteoporosis. The NHS website has more information about giving up smoking.

  • Alcohol

    Drinking alcohol in moderation is not harmful to bone health. But if you often drink more than the government guidelines advise, your bone density may be reduced. This can increase your risk of osteoporosis.

    It is best to keep to the guidelines of not drinking more than 14 units of alcohol a week. If you regularly drink as much as 14 units per week, it is best to spread your drinking evenly over 3 or more days. You should also try to have several alcohol-free days a week.

    Drinking alcohol also causes a higher risk of falls, which are a common cause of fractures.

  • Medical conditions

    Some medical conditions have been linked to lower bone density. These include:

    • diabetes (type 1 and type 2)
    • asthma
    • inflammatory rheumatic diseases, such as rheumatoid arthritis and lupus (SLE)
    • inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis
    • long-term liver or kidney disease
    • thyroid diseases, for example an overactive thyroid gland
    • eating disorders, such as anorexia.

    If you have difficulty walking or a condition that makes you less mobile, this may lead to a lower bone density.

  • Medicines

    Some drugs may increase your risk of fractures and of developing osteoporosis. These include the following:

    • Steroids – these are given to treat illnesses such as rheumatoid arthritis and asthma. They may also be used with some cancer treatments.
    • Some anti-epileptic drugs – these are used to prevent fits (seizures) if you have epilepsy.
    • Some types of cancer treatments.

We have more information about taking care of your bone health.

Tests to check your bone health

If you think you are at risk of weak bones, talk to your GP or hospital doctor. They can do tests to check your bone health.

Fracture risk assessment tools

Doctors in the UK use two online tools to see whether you are at risk of a fragility fracture. These are called FRAX® and QFracture®. Your doctor may use one of these tools if they are concerned about your bone health, or if you have risk factors for bone loss.

When your doctor uses the online tool, they will ask about your: 

  • height
  • weight
  • medical history
  • possible risk factors for osteoporosis or fragility fractures.

The online tool then works out your risk of developing a fracture. The results will show whether you have a low, intermediate or high risk of a fracture.

DXA scan

Your GP or hospital doctor may also arrange for you to have a scan to check your bone density. This is called a dual energy x-ray absorptiometry scan (DXA or DEXA scan). It is sometimes called a bone mineral density (BMD) scan.

We have more information about having a DXA scan.

Treatments to protect your bones

You may have drug treatments to protect your bones if:

  • tests show you have low bone density or a high risk of fracture
  • you are having cancer treatments that are known to increase your risk of osteoporosis.

Treatments to protect your bone may include:

We have more information about these and other drug treatments to protect the bones and possible side effects.

If your GP or hospital doctor thinks you need specialist advice for osteoporosis, they may refer you to a hospital team that specialises in it. These teams may include doctors, nurses and physiotherapists who work closely with occupational therapists and pain specialists.

What you can do to look after your bones

You can make changes to your lifestyle to improve your bone health and reduce your risk of osteoporosis. If you have a high risk of fractures, your doctor may advise you to:

  • eat a healthy, balanced diet
  • get enough sunshine (if this is possible)
  • keep physically active.

These changes are helpful for everyone, not just people affected by cancer. We have more detail in our information about looking after your bones.

Share your experience

If cancer treatments have affected your bone health, you may find it helpful to talk about it with other people. Sharing your thoughts and feelings with others can help them too. Hearing about how you have coped and what you have done to manage your bone health could help someone in a similar situation.

There are also opportunities to influence future healthcare by sharing your experiences. You could do this by:

  • joining a patient group or online forum
  • volunteering with a cancer charity
  • taking part in research
  • telling NHS staff what you think about the care you received, or the care you would like to have received.

You may also like to join the Macmillan Online Community.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 September 2020
Next review: 01 September 2023

This content is currently being reviewed. New information will be coming soon.

Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.