High calcium in people with cancer

When you have more calcium in your blood than normal it is called hypercalcaemia. It’s pronounced high-per-kal-see-mee-a. It is a serious but treatable condition.

High blood calcium levels sometimes happen if your cancer is advanced. It is less likely to happen if your cancer is at an early stage.

It is important to contact the team caring for you if you have symptoms of high calcium. A high blood calcium level can make you feel very unwell. Your doctor will want to start treatment as soon as possible. 

Symptoms

Many of the symptoms of high calcium are common in advanced cancer, even in people who do not have high blood calcium levels. You might not have any definite symptoms. You may just feel a bit unwell or very tired.

How serious your symptoms are doesn’t always match up to the calcium level in your blood. It is important to talk to your doctor if you are worried that you might have a high blood calcium level. People with a slightly high calcium level can have very severe symptoms and people with a very high calcium level might only have mild symptoms.

Your doctor will do a blood test if they think that the levels might be high.

First symptoms

Some of the first symptoms that your blood calcium level might be higher than normal include: 

• feeling more tired than usual
• feeling weak
• not wanting to eat much
• constipation
• loss of concentration and interest in doing things
• mild confusion
• low mood
• irritability

Untreated high calcium symptoms

If you don't have treatment your symptoms can become much worse. It could lead to you becoming unconscious and eventually be life threatening. The symptoms of a high calcium level can include:

• feeling and being sick
• drowsiness
• passing large amounts of urine
• feeling very thirsty or dehydrated
• confusion or agitation
• muscle spasms
• tremors
• bone pain and weakness
• irregular heartbeat
• difficulty thinking and speaking clearly

Brain and spinal cord symptoms

Calcium plays a role in the normal working of the brain and spinal cord. So if you have severely high calcium levels you might also:

• have fits (seizures)
• be unable to coordinate muscle movement, which can affect walking, talking and eating
• have changes in personality

Why people with cancer can have high blood calcium levels

Normally the body controls the level of calcium in the blood very well. High blood calcium levels in the body can happen if:

• your cancer is interfering with the control of the amount of calcium in the bloodstream 
• you have cancer in your bones which is causing a release of calcium into the bloodstream
• you have dehydration from being sick or having diarrhoea, this is not a common cause 

Which cancers might cause high calcium?

The types of cancers that are most commonly associated with high blood calcium are:

• myeloma – about 30 in 100 people (about 30%) have high calcium when they are first diagnosed
• breast cancer
• lung cancer
• kidney cancer
• prostate cancer

Although less common, high blood calcium can happen in other types of cancer.

Treatment

Your specialist will treat you if you have high calcium levels. You might have to have treatment in hospital.