Zoledronic acid (Zometa) for primary breast cancer

Zoledronic acid is a drug given to reduce the risk of breast cancer coming back and spreading to the bones and other parts of the body.

You may hear it called by its brand name Zometa.

Zoledronic acid belongs to a group of drugs called bisphosphonates.

Bisphosphonates slow down or prevent loss of bone tissue.

In our bodies, whether we have cancer or not, bone tissue continually breaks down and is replaced with new bone tissue. This is a natural process called bone remodelling.

Breast cancer cells seem more likely to spread to areas where bone remodelling takes place. This is why, if breast cancer spreads, it commonly affects the bones.

Bisphosphonates like zoledronic acid are absorbed in areas of the body where there is a lot of bone remodelling.

This may help reduce the risk of breast cancer spreading to the bones.

Primary breast cancer

Zoledronic acid is suitable for some people with primary breast cancer.

You may be prescribed zoledronic acid if you’ve been through the menopause (postmenopausal). It can be used whether the menopause happened naturally or because of breast cancer treatment. 

If you haven’t been through the menopause or you’re a man with primary breast cancer, zoledronic acid won't benefit you.

You may be offered zoledronic acid if:

• You’ve had treatment for invasive breast cancer that has spread to the lymph nodes under the arm 

• Your cancer hasn’t spread to the lymph nodes but you have other factors that increase the risk of the cancer returning 

Other uses of zoledronic acid

Zoledronic acid is also prescribed:

• For people who are at risk of, or who have, osteoporosis

• As treatment for metastatic (secondary) breast cancer in the bone

You’ll usually start zoledronic acid within 3 months of your final surgery.  

If you’re having chemotherapy after surgery, you’ll usually start zoledronic acid within 2 months of finishing chemotherapy. You may have your first bisphosphonate treatment with your last cycle of chemotherapy. 

Zoledronic acid is given as a drip (infusion) into a vein in your hand or arm (intravenously).

The infusion is usually given in the chemotherapy department of your hospital and takes about 15 minutes.

You usually have an infusion of zoledronic acid every 6 months for 3 to 5 years.

Zoledronic acid can cause side effects. Side effects vary between people and can usually be managed.

Talk to your GP or treatment team if you’re worried about any side effects, even if they’re not listed here.

Common side effects

Common side effects happen to more than 10 in every 100 people who take the drug.

Flu-like symptoms

Zoledronic acid can cause flu-like symptoms such as:

• Joint and muscle pain

• Extreme tiredness (fatigue)

• Shivering

• High temperature (fever)

These symptoms can last for a few days.

Your treatment team can advise you about taking mild pain relief to help.

Feeling sick or being sick

This is usually mild and can last a few days. Your treatment team can prescribe anti-sickness drugs to help.

Headache

You may have a headache that lasts from a few hours to a few days after your infusion.

Let your treatment team know if you get headaches as they can advise you about taking mild pain relief.

Red or sore eyes

Your eyes may be sore or red for a few days after your treatment. Your treatment team can prescribe eyedrops to relieve this.

Occasional side effects

Occasional side effects happen to between 1 and 10 in every 100 people who take the drug.

Diarrhoea

This is usually mild. Your treatment team can prescribe anti-diarrhoea medication to help control this. 

Contact your treatment team if you have diarrhoea 3 or more times in 24 hours, compared to what’s usual for you.

Drink plenty of fluids to avoid getting dehydrated. 

Low calcium levels in the blood

Zoledronic acid can cause calcium levels in the blood to drop too low. This is called hypocalcaemia.

You’ll have regular blood tests to check your calcium levels.

Early symptoms of hypocalcaemia include tingling around the mouth and lips and in the hands and feet. Let your treatment team know if you have any of these.

Your treatment team may recommend calcium and vitamin D supplements. You can also ask them for advice on how to maintain a good level of calcium and vitamin D in your diet. You can find out more in our information on looking after your bones.

Rare side effects

Rare side effects happen to fewer than 1 in 100 people who take the drug.

Anaemia

Having too few red blood cells is called anaemia.

Tell your treatment team if you feel particularly tired, breathless or dizzy.

You may have regular blood tests throughout your treatment to check red blood cell levels.

Allergic reaction

Zoledronic acid can sometimes cause an allergic reaction.

Call 999 or go to A&E if you have any of the following symptoms:

• Breathlessness, wheezing, a bad cough or sudden difficulty breathing 

• Tight chest or chest pain 

• Swelling in your lips, tongue or throat 

• Itchy red or discoloured bumps on your skin (these may be harder to see on black or brown skin)

Some reactions can start during the infusion or immediately afterwards. Some may develop days after.

Osteonecrosis

Zoledronic acid can cause some of the jawbone to lose its blood supply and die. This is called osteonecrosis of the jaw (ONJ). It’s a rare but serious side effect of zoledronic acid.

Your treatment team will recommend you see a dentist before starting zoledronic acid. If you don’t have a dentist or you’re having difficulty registering with one, let your treatment team know.

If you need a dental procedure, such as having a tooth removed, your treatment team or dentist can tell you if you’ll need to wait or stop treatment first.

ONJ is hard to treat so trying to prevent it is very important. Looking after your teeth and gums can help reduce the risk of developing it. This includes brushing your teeth and flossing, making sure dentures fit well and having regular dental check-ups.

There’s evidence that smoking increases the risk of developing ONJ. Speak to your treatment team or GP if you need support with stopping smoking.

It’s not clear how long the risk of ONJ continues for once the treatment ends.

In rare cases, osteonecrosis can affect the ear. Tell your treatment straight away if you have ear pain, discharge from your ear or an ear infection while having zoledronic acid.

Broken bone (fracture)

Although it’s rare, zoledronic acid can cause the large bone in the upper leg (femur) to fracture. It’s not fully understood why this happens.

Tell your treatment team if you have lasting pain in your thigh, hip or groin.

Effects on the kidneys

Zoledronic acid can affect the way the kidneys work.

You’ll have blood tests before and throughout treatment to monitor this.

Becoming pregnant while you’re having zoledronic acid is not recommended. This is because it’s not known whether zoledronic acid can harm a developing baby.

Your treatment team can advise you on what contraception to use and how long you should use it before and after treatment.

It’s important to let your treatment team know if you’re pregnant before starting treatment, or if you become pregnant during treatment with zoledronic acid.

If you’re thinking about becoming pregnant after you’ve finished your treatment with zoledronic acid, talk to your treatment team.

If you have any worries or questions about zoledronic acid, you can call our nurses free on 0808 800 6000 to talk through your concerns. You can also email nurse@breastcancernow.org

You can find out more about our support services below.