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High calcium in people with cancer

Coping with cancer

This page has information about high calcium levels (hypercalcaemia) in people with cancer. There is information about


Why people with cancer get hypercalcaemia

Between 10 and 20 out of every 100 people with cancer (10 to 20%) develop hypercalcaemia. This usually happens in the advanced stages of cancer and is rare in people with earlier stages.

The cancer makes calcium leak out into the bloodstream from your bones, so the level in the blood gets too high. The cancer may also affect the amount of calcium that your kidneys are able to get rid of. If you have bone secondaries, damaged areas of bone can release calcium into your bloodstream. 

Dehydration from being sick a lot or having diarrhoea may also increase calcium levels. It is very important that you do something about this. If not treated, hypercalcaemia can make you more and more drowsy until you are sleeping nearly all the time. If still not treated, you may go into a coma and eventually die. The types of cancers that are most commonly associated with hypercalcaemia are

Although less common, hypercalcaemia can affect people with other types of cancer.


Symptoms of hypercalcaemia

It is not always easy for a doctor to spot that you have hypercalcaemia. You may not have any specific symptoms. It may be that you just feel a bit unwell or very tired. And the severity of your symptoms doesn’t always match up to the calcium level in your blood. People with a slightly high calcium level can have very severe symptoms, and people with a very high calcium level may only have mild symptoms. Many of the symptoms are common in the advanced stages of cancer, even in people who do not have hypercalcaemia.

All this can make it difficult for your doctor to pick hypercalcaemia up. But the first signs may include

  • Extreme tiredness (fatigue) and lethargy
  • Feeling weak
  • Not wanting to eat much (anorexia)
  • Constipation
  • Loss of concentration and interest in doing things
  • Mild confusion

If the hypercalcaemia is not treated the symptoms become much worse and can include

  • Feeling and being sick
  • Drowsiness
  • Passing large amounts of urine
  • Feeling very thirsty
  • Dehydration
  • Confusion
  • Agitation
  • Muscle spasms, tremors.
  • Bone pain and weakness
  • Irregular heart beat
  • Difficulty thinking and speaking clearly
  • Coma and finally death, if not treated

Because calcium plays a role in the normal working of the brain and spinal cord, patients with severe hypercalcaemia may also

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

If you have hypercalcaemia, you will need treatment from your specialist. It can be a life threatening condition if it is not treated. You may have to spend a day or two in hospital to get your calcium levels down. There is detailed information about managing hypercalcaemia in the next section.

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Updated: 18 March 2014