Complexed PSA Test More Accurate than Total PSA

A study has found that the measurement of serum concentration of complexed prostate-specific antigen (cPSA) is more accurate than the total PSA (tPSA) used by most doctors. The results are reported in the November 2003 issue of The Journal of Urology.

The study was conducted at seven prostate cancer treatment centers, where serum was collected from 831 men about to undergo initial prostate biopsy. The biopsies showed that 313 (37.5%) had prostate cancer. Knowing which patients actually had prostate cancer, the investigators compared the accuracy of the predictions of the cPSA and tPSA tests. The found that cPSA was significantly more predictive of cancer than tPSA and also provided better specificity. For example, in the range of 2-4 ng/ml, both tests correctly identified cancer 85% of the time, but the cPSA test correctly identified 35% of patients who did not have cancer, compared to only 21.2% for the tPSA test. Thus, the cPSA test would have saved 14% from undergoing an unnecessary biopsy.

"Urologists are increasingly looking at the lower range of PSA values to maximize the detection of prostate cancer,” said investigator Richard Babaian, M.D., from the M.D. Anderson Cancer Center (Houston, TX, USA). "Since this lower range also includes many men without cancer, the enhanced specificity of the cPSA test to detect those who are cancer free and avoid unnecessary biopsies is an important advantage over the standard tPSA test.” The cPSA test used in the study is the product of Bayer Diagnostics (Tarrytown, NY, USA).




Related Links:
Bayer Diagnostics