A simple blood test could detect early signs of deadly 'asbestos cancer', scientists have claimed.
Asbestos dust remains a major health hazard
Patients with mesothelioma - often caused by exposure to asbestos - often die within a few years of diagnosis.
But in a study published in The Lancet, researchers say checking levels of a key protein can identify over 80% of cases at an early stage.
Earlier detection would mean doctors could treat the patient using chemotherapy, radiotherapy or surgery.
Mesothelioma affects the mesothelial tissue surrounding the lungs.
The aggressive cancer develops decades after asbestos exposure.
But not all those who worked with asbestos go on to develop the cancer, and Australian scientists were looking for a way of identifying who was at risk.
Researchers from the Sir Charles Gairdner Hospital, Perth, Australia, developed a test to assess blood concentrations of soluble mesothelian related (SMR) protein, which has been shown to be an indicator of other cancers.
The scientists believed high levels of SMR might also be seen in asbestos cancer patients.
They obtained blood samples from patients attending respiratory clinics in Perth between 1997 and 2002 and tested their SMR levels.
Thirty-seven people out of 44 with mesothelioma had high SMR levels - an 84% accurate detection rate.
Out of seven people who had been exposed to asbestos who also had increased blood concentrations of SMR, three went on to develop mesothelioma and one lung cancer within five years of the study.
But none of the 33 people exposed to asbestos who had normal concentrations of SMR developed mesothelioma in that time.
And only three out of 160 patients with other cancers or other inflammatory lung diseases, and none of the 28 controls who had not been exposed to asbestos had raised SMR levels.
The researchers said their findings indicated SMR could be a useful way to monitor the growth of mesothelial tumours because concentrations were seen to increase during tumour progression.
Improving patients' chances
Dr Bruce Robinson, who led the research, said: "On the basis of our data we propose that measurement of SMR concentrations in serum is a useful adjunct in the diagnosis of mesothelioma.
"Blood SMR concentrations should be monitored in asbestos-exposed individuals who are at risk of developing mesothelioma to determine if early therapeutic intervention improves patients' outcome."
He added: "Importantly for the hundreds of thousands of asbestos-exposed people who are at risk of this cancer, the test can detect the cancer several years before it presents."
Dr Siow Ming Lee, a lung cancer specialist and spokesman for Cancer Research UK: "These findings are interesting but they need to be validated in a larger study.
"You would need to make sure that the test did not give a false-positive result - and be aware that the presence of the protein could indicate other cancers as well."