PCA3, a Relatively New Marker for Prostate Cancer

Monday, 17/12/2012  |   Prostate Cancer, Reports  |  no comments

This test might lower the number of biopsies driven by prostate-specific antigen testing. Prostate cancer gene 3 (PCA3) is overexpressed in prostate cancer cells. Its product can be measured in urine specimens collected after digital rectal exams; FDA-approved assays are available for clinical use. To determine how PCA3 might help clinicians decide which patients with elevated prostate-specific antigen (PSA) levels should undergo biopsies, researchers conducted this study of 1913 men with PSA levels 2.5 ng/mL. All men underwent PCA3 testing before undergoing biopsies. Biopsies were positive for cancer in 42% of patients. If only men with PCA3 scores 35 had undergone biopsies, about 1300 men would have avoided procedures, but about 400 of the 800 cancers would have been missed. In contrast, if the cutoff for a positive PCA3 score were lowered to 10, only about 100 of the 800 cancers would have been missed, but only about 500 men would have avoided biopsies. Comment: Primary care clinicians should be aware of PCA3, which urologists are using increasingly to make decisions about prostate biopsy — especially for patients who are followed after previous negative biopsy results. The sensitivity and specificity of PCA3 vary considerably depending on the cutoff used; a cutoff of 25 (midway between the cutoffs discussed above) is suggested for a recently approved PCA3 assay. But whether PCA3 ultimately will do what its proponents hope — lower prostate cancer mortality and also lower the biopsy rate — remains unclear. Citation: Crawford ED et al. Diagnostic performance of PCA3 to detect prostate cancer in men with increased prostate specific antigen: A prospective study of 1,962 cases. J Urol 2012 Nov; 188:1726. (http://dx.doi.org/10.1016/j.juro.2012.07.023)

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