Platelet test found to predict cancer risk, research finds

A large-scale study carried out by the University of Exeter has indicated that having a high blood platelet count is a strong predictor of cancer and should be urgently investigated to save lives.

A study of 40,000 patient records published in the British Journal of General Practice found that more than 11 per cent of men and six per cent of women over the age of 40 with thrombocytosis went on to be diagnosed with cancer within a year. This rose to 18 per cent of men and 10 per cent of women if a second raised platelet count was recorded within six months.

Statistics show that in the general population, around one per cent develop cancer in any one year.

In the cohort analysed, of people who had been sent for a blood test by their GP, around four per cent of men and two per cent of women developed cancer. Lung and colorectal cancer were more commonly diagnosed with thrombocytosis. One-third of patients with thrombocytosis and lung or colorectal cancer had no other symptoms that would indicate to their GP that they had cancer.

The paper has called for GPs to consider a diagnosis of cancer in patients with unexpected thrombocytosis, to increase early diagnosis which can save lives.

Lead author Dr Sarah Bailey, of the University of Exeter Medical School, said: “We know that early diagnosis is absolutely key in whether people survive cancer. Our research suggests that substantial numbers of people could have their cancer diagnosed up to three months earlier if thrombocytosis prompted investigation for cancer. This time could make a vital difference in achieving earlier diagnosis.”

Professor Willie Hamilton, of the University of Exeter Medical School, said: “The UK lags well behind other developed countries on early cancer diagnosis. In 2014, 163,000 people died of cancer in this country. Our findings on thrombocytosis show a strong association with cancer, particularly in men – far stronger than that of a breast lump for breast cancer in women. It is now crucial that we roll out cancer investigation of thrombocytosis. It could save hundreds of lives each year.”