cPSA More Accurate for Detecting Prostate Cancer

A new study has confirmed that measuring the concentration of complexed prostate specific antigen (cPSA) is more accurate than total PSA for the detection of prostate cancer.

The study evaluated the predictive accuracy of both cPSA and total PSA by comparing results from serum samples obtained from a group of 831 men, 313 of whom were known to have prostate cancer. cPSA was found to be significantly more predictive than total PSA, providing an improvement in specificity, compared to total PSA. This means that using the cPSA test will result in fewer false-positives and unnecessary biopsies than using the standard PSA test.

Urologists are increasingly looking at the lower range of PSA values to be sure they catch possible cases of prostate cancer. Since this lower range also includes many men without cancer, the greater specificity of the cPSA test is an important advantage over the PSA test. Current methods for measuring total PSA levels generate false-positive results of up to 60% of cases, because PSA levels can also be raised as a result of other factors, such as noncancerous enlargement of the prostate, acute infections, and prostate surgery.

A complexed prostate specific antigen (cPSA) assay for use on the Advia Centaur and Immuno 1T automated immunoassay systems from Bayer Diagnostics (Tarrytown, NY, USA) measures PSA complexed to alpha-1-anti-chymotrypsin, one of the major PSA complexes involved in prostate cancer. The assay facilitates accurate and specific cPSA measurement, eliminating the need for laboratorians to perform any calculations and enabling them to benefit from the efficiency and convenience of automated analysis, which saves time and reduces costs.

"The findings of this study are important because they suggest that use of the assay can decrease the number of unnecessary prostate cancer biopsies, particularly if a lower PSA threshold is utilized,” notes Fiona Howe, product manager for the cPSA assay at Bayer. "This approach not only has the potential to save healthcare expenditures but will also spare many men the discomfort and anxiety associated with invasive biopsy procedures.”

The study, led by Dr. A.W. Partin, was conducted by researchers at Johns Hopkins Medical Institutions (Baltimore, MD, USA) and was published in the November 2003 issue of the Journal of Urology.




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