Posted on May 19, 2009, 5 p.m.
By gary clark
Early results of a new faster prostate cancer test are promising; however, researchers still need to determine if the test is accurate over a large number of samples.
Each year, about 34,000 men are diagnosed with prostate cancer in the United Kingdom, of which 10,000 die from the disease. And in the United States, the American Cancer Society estimates that by the end of 2009, about 192,280 new cases of prostate cancer will be diagnosed - and of those, 1 in 35 will ultimately die of the disease. The most common diagnostic testing method is the prostate-specific antigen (PSA) blood test. The PSA test is often unreliable, producing false results when the PSA level is elevated and there is no cancer, or when the PSA level is normal and there is cancer. Because of this, a biopsy is usually performed to confirm or rule out cancer when the PSA level is high. Patients have to wait two weeks for results.
Now, a team of scientists from the University of Durham in the UK have developed a new three-minute test for the diagnosis of prostate cancer in collaboration with the University of Maryland. The test detects changes in the wavelength of light as it shines through diluted samples of prostate fluid, measuring levels of a molecule called citrate. Citrate levels drop significantly during the earlier stages of prostate cancer. As Lead Researcher Professor David Parker says, "It's been a complex process to develop the technique, but we're very optimistic about it. Ultimately, this could provide an accurate method of screening for prostate cancer in men that could be carried out in three minutes once a biopsy has been obtained from the patient at a hospital outpatient department."
Currently, the test is conducted on a sample of prostate fluid taken with a needle under local anesthetic. The ultimate goal is to be able to use semen, rather than the fluid, which would make the test much more user-friendly and potentially more useful. "This new test, which involves the insertion of a needle into the prostate under local anesthetic, is an invasive procedure," notes Prostate Cancer Charity chief executive John Neate, who also stressed that the research is at an early stage and that work still needs to be done to ensure that the test is accurate over a larger number of samples. "The researchers hope to able to refine the test by using samples of seminal fluid which may be easier to obtain," he says. "If this was the case, it would be easier to see how this test could take a useful place in clinical practice." In theory, a result that can be gained more quickly could allow doctors to begin treatment faster in the cancer's earlier stages, when it has the greatest chance of being effective.
News Release: Hope of fast prostate cancer test www.news.bbc.co.uk Mary 18, 2009