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The study: Researchers developed a new urine test to detect prostate cancer and predict how quickly it may grow and spread. The test can identify if two genes, TMPRSS2 and ERG are joined together, which is associated with cancer that grows and spreads more quickly. A previous study of tumor tissue samples showed that these genes may be used to diagnose prostate cancer. In the study, researchers analyzed urine samples from 556 men who were scheduled to have a prostate biopsy after having a digital rectal examination (DRE; a test to check the surface of the prostate for any irregularities). The results of the biopsy were compared to the results of the urine test to determine if the urine test could be used to detect prostate cancer. Usually, a biopsy (removal of a tissue sample for examination under a microscope) is the only way to make a definitive diagnosis of prostate cancer.
The most commonly used method to determine if a man needs a biopsy to check for prostate cancer is the prostate-specific antigen (PSA) test. A PSA test detects higher-than-normal levels of PSA, a type of protein released by prostate tissue that can indicate the presence of prostate cancer. However, a PSA test cannot predict how quickly a cancer may grow and spread, and it often detects early prostate cancers which are slow-growing and unlikely to be life threatening. Men with such slow-growing prostate cancers are sometimes monitored with regular PSA testing and biopsies as needed, a method called active surveillance.
The results: After the men received prostate biopsies, 226 (41%) were diagnosed with prostate cancer. The new urine test correctly predicted that 85% of these men had prostate cancer, compared with 27% for a PSA test alone. The urine test also found that 42% of the men with prostate cancer had TMPRSS2 and ERG genes that were joined together. These results are similar to other studies that have shown that for about half of men with prostate cancer these genes are joined together.
What this means for patients
“This urine test showed it can accurately detect prostate cancer. We also found that TMPRSS2 and ERG levels correlated with other factors, such as tumor size and stage, that can help predict a patient's chance of recovery. These results suggest that this urine test could be used, along with other information, to help determine which men can be monitored and which may require more aggressive treatment,” explained lead author Jack Groskopf, PhD, Director of Research and Development in the Cancer Diagnostics Division of Gen-Probe Incorporated, the manufacturer of the urine test. This test is not yet available at all hospitals, and research on the test is ongoing. Talk with your doctor about other types of prostate cancer screening tests.
Questions to Ask Your Doctor
- What is my risk of prostate cancer?
- What screening tests do I need to have to detect prostate cancer?
- What tests will I need if something abnormal is found during a DRE or PSA test?
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