A new blood test could help change the way cancer is diagnosed, it has been claimed.
Researchers from the Royal Brompton Hospital and the National Heart and Lung Institute (NHLI) at Imperial College London hope that it might one day be available in GP surgeries to provide a diagnosis within days and the chance of earlier treatment.
The test which helps to identify cancer-specific gene mutations in the DNA could be "a real game changer" in the diagnosis and treatment for all types of cancer, according to consultant thoracic surgeon Eric Lim, who led a study on blood tests from 223 patients.
Researchers were not told whether patients, who were all pre-surgery for known or suspected lung cancer, had already received a definitive diagnosis.
Using the blood test, they were able to correctly identify cancer-specific gene mutations in the DNA of nearly seven out of ten patients who were later confirmed to have cancer.
DNA was extracted from the plasma (the fluid part of the blood) and analysed to identify three common gene mutations.
Cancerous tissue was also analysed for these genetic abnormalities to see how closely it could be linked to the blood sample. These cancer-specific gene mutations are not usually found in the blood of healthy individuals.
In presenting the findings at the annual World Conference on Lung Cancer in Colorado, US, Mr Lim warned: "The test is not an alternative to a biopsy for all patients, but when a blood test shows a positive result, this could mean a patient is saved from going through an unnecessary and invasive diagnostic procedure.
"It might also result in patients having earlier imaging scans and beginning treatment sooner."
Biopsies, or tissue samples, are often taken with a needle during a CT scan. It can lead to complications for a small number of patients.
The new blood test, which researchers estimate would cost the NHS a few hundred pounds, could be a less invasive but still accurate method for a large number of patients with suspected cancer.
Patients with primary or secondary lung cancer were the focus of the study which found they shared gene patterns which are common to patients with other forms of cancer, such as colorectal cancer.
This indicates the blood test could be useful in suggesting the presence of other cancers, it was suggested.
Mr Lim, of the Royal Brompton & Harefield NHS Foundation Trust, noted that other conventional diagnostic methods would still be needed.
A negative result from the blood test would not completely rule out the presence of cancer cells, he added.
More research and on a wider scale is needed to back up the initial findings before any attempt could be made to use it in a clinical setting.
Mr Lim said: "We hope that further research will also make the blood test even more effective as a diagnostic tool."