Bone health and early breast cancer treatment

You can take steps to improve your bone health during and after treatment. Your breast cancer specialist can talk to you about ways to keep the bones strong and less likely to break.

How breast cancer treatment affects bone health

Long-term changes in your bone density can happen when your treatment includes:

• chemotherapy
• hormone-blocking therapies
• ovarian suppression.

Lower bone density increases your risk of developing osteoporosis. When you have osteoporosis, your bones are more fragile and brittle and more likely to break.

Generally, osteoporosis does not cause any pain or other symptoms. You may not know you have it until you break (fracture) a bone.

The most common sites for fractures are:

• wrists
• hips
• spine.

Chemotherapy

Some chemotherapy medicines can have a direct effect on your bone health.

If chemotherapy causes you to go into an early menopause, this also contributes to bone loss. During menopause, women produce less oestrogen, which can result in lower bone density.

Bone loss may begin while you're having chemotherapy and continue after you finish treatment.

Post-menopausal women may also have greater loss of bone density due to chemotherapy.

Ovarian suppression

Ovarian suppression is often given to premenopausal women with breast cancer.

Ovarian suppression stops the ovaries from producing oestrogen, either:

• temporarily, with monthly injections of goserelin (Zoladex)
• permanently, with radiotherapy or surgery to remove the ovaries.

Having less oestrogen can be good for cancer treatment but can lower bone density.

Hormone-blocking therapy (tablets)

Aromatase inhibitors are hormone-blocking therapies that lower the oestrogen in your body. For women who are already at risk of bone thinning, this can lead to osteoporosis and bone fractures.

Examples of aromatase inhibitors are anastrozole, letrozole and exemestane.

These treatments only work in postmenopausal women. Some premenopausal women take an aromatase inhibitor as well as an ovarian suppression treatment. This can reduce bone density.

If your doctor prescribes an aromatase inhibitor, they may suggest:

• a test to measure your bone density, usually a DXA (or DEXA) scan
• checks on your vitamin D and calcium levels as they are important for bone health. Vitamin D helps your body to absorb calcium.

Tamoxifen (Nolvadex) is a commonly used therapy for hormone receptor positive breast cancers. It blocks the effect of oestrogen on cancer cells.

In premenopausal women, tamoxifen can reduce bone density but usually only by a small amount.

In post-menopausal women, tamoxifen is shown to protect the health of bones by reducing bone loss.