Prostate cancer is a relatively common type of cancer among men above 50 years of age. Prostate is a small walnut-sized gland located above the urinary bladder, surrounding the upper part of the urethra. This form of cancer usually remains unnoticed as no symptoms appear in the early stages of the disease. As the disease progresses, the cancer may spread to other areas of the pelvis and may cause obstruction in urinary outflow or bone pain.
Prostate cancer is reported to be the second leading cause of cancer death among men. Among all the diagnostic tests commonly carried out to screen prostate cancer, Prostate-Specific Antigen (PSA) blood test is the most effective one. It detects upto eighty percent of prostate cancers but a chance of false-positive is high with this test.
A new form of the Prostate-Specific Antigen (PSA) test called Complexed PSA or cPSA is now available to screen for prostate cancer. Some organizations are touting cPSA as a more accurate form of PSA blood testing for the detection of early stage prostate cancer, but an abnormal result does not constitute conclusive diagnosis of cancer.
PSA exists in three major forms in the blood: 1) free, 2) bound to a protein called alpha-1-antichymotrypsin and 3) bound to another protein called alpha-2-macroglobulin. People with prostate cancer have more of the form bound to alpha-1-antichymotrypsin and less of the free form as compared to healthy men or those with benign diseases of the prostate. Initial screening for prostate cancer commonly uses the total PSA test, which measures all but the third form of PSA. In case slightly elevated results appear then a follow-up test to measure free PSA is recommended. This however leads to many false-positive and false-negative results. Whereas the new cPSA test would replace these so that only a single screening test would be needed.
According to a large scale study that included researchers from John Hopkins and the New York University School of Medicine, the cPSA test demonstrated improved specificity a over total PSA assay, reducing the number of false-positives and leading the investigators to conclude that cPSA could be used as a first-line test for prostate cancer screening.
Doctors mostly recommend that men above 50 years should get themselves screened for prostate cancer even though they may not have any symptoms. However, one must consult a doctor before undergoing this test.