LONDON (Reuters) - British scientists say they have developed a lab test that can accurately distinguish prostate cancer from healthy tissue and other prostate conditions -- a finding that may in future help men avoid unnecessary treatment.
Researchers at a genetics and diagnostics firm Oxford Gene Technology (OGT) say the set of biological signals, or biomarkers, they have identified was able to distinguish healthy tissue and benign prostate disease from prostate cancer with 90 percent accuracy in initial laboratory sample tests.
A full test for use in doctors’ clinics is likely to be at least five years off, they said, but their pilot study testing around 130 samples showed encouraging results in a disease area where more accurate diagnostic tests are sorely needed.
Prostate cancer killed an estimated 258,000 people in 2008 and is the second most common cause of cancer death in men in the United States.
The most effective screening tests currently available are based on a single biomarker called prostate specific antigen (PSA). But PSA testing is problematic because it has low specificity, which generates high false positive rates and leads to unnecessary surgical and radiotherapy treatment.
A U.S. study published last year found that routine PSA prostate screening has resulted in more than one million American men being diagnosed with tumors who might otherwise have suffered no ill effects from them.
“There is a real need for a test that is very sensitive, i.e. something that will pick up prostate cancer -- but also something very specific i.e. that it won’t get confused by other diseases or conditions that men in that age group may suffer from,” John Anson, vice president of biomarker discovery at OGT, said in a telephone interview.
“Our pilot test was encouraging because we were able to discriminate between samples from those who were known to have prostate cancer, the benign prostate conditions and the healthy ones, with levels of accuracy and specificity that were much better than the conventional clinical test.”
Anson, who presented his findings at a conference on cancer diagnostics in the United States on Tuesday, said the test was designed to detect so-called autoantibodies -- antibodies produced by the immune system to attack the body’s own proteins.
Although they are more commonly linked to autoimmune diseases such as lupus or Type 1 diabetes, the immune system also produces autoantibodies in response to other diseases, including cancer, because of changes that occur in proteins during the course of the disease.
“Our screening test...is looking at the prevalence of these autoantibodies as early indicators of disease,” Anson said.
He said this not only suggested the test could work as a very early warning system for prostate cancer, but could also have potential as an early test for other forms of cancer too.
The researchers said they were now using testing their findings on 1,700 samples taken from prostate cancer patients, people with no cancer, patients with other cancers and patients with other prostate diseases. They are also doing tests on bowel cancer and a type of cancer called non-small cell lung cancer.
Editing by Noah Barkin