Calcium in the blood could provide an early warning of cancers, especially in men, research has shown. Even slightly raised blood levels of calcium in men was associated with an increased risk of cancer diagnosis within one year. The discovery, reported in the British Journal of Cancer, raises the prospect of a simple blood test to aid the early detection of cancer in high risk patients.
Hypercalcaemia – a higher than normal calcium reading – was associated with various cancers, chiefly lung, prostate, breast, bowel, and those affecting the blood such as leukaemia and myeloma. While the condition was known to occur in up to a fifth of cancer patients, this is the first time it is shown to pre-date diagnosis.
Lead researcher Dr Fergus Hamilton, from the Centre for Academic Primary Care at the University of Bristol, said: “All previous studies on hypercalcaemia and cancer had been carried out with patients who had already been diagnosed with cancer – hypercalcaemia was seen as a late effect of the cancer.
“We wanted to look at the issue from a different perspective and find out if high calcium levels in blood could be used as an early indicator of cancer and therefore in the diagnosis of cancer.”
The Bristol team analysed the records of 54,000 patients listed on an electronic GP database to see how many with a history of hypercalcaemia went on to receive a cancer diagnosis.
A normal level of calcium in the blood is between 2.1 and 2.5 millimoles per litre (mmol/L). In men, even a slight increase outside this range was found to increase the risk of cancer being diagnosed within one year by 11.5 per cent. Above 2.8 mmol/L, the risk rose to 28 per cent.
Dr Safia Danovi, research funding manager at Cancer Research UK, said: “Diagnosing cancer earlier is one of the key ways to improve the chances of survival. This research suggests that measuring calcium levels in the blood could help doctors decide whether to send a patient for further tests, but we don’t know whether it could lead to earlier diagnosis or improved survival.”