PCA3 Materials & News

Ploussard G, Haese A, van Poppel H, Marberger M, Stenzl A, Mulders PFA, Huland H, Bastien L, Abbou C-C, Remzi M, Tinzl M, Feyerabend S, Stillebroer AB, van Gils MPMQ, Schalken JA, de la Taille A. BJU Int 2010;106:1143-7

• This subanalysis of the European repeat biopsy study¹ shows that in 301 men with a prior negative biopsy and a serum total PSA level 2.5-10 ng/mL, the diagnostic performance of the PCA3 Score was independent of the free/total PSA ratio (f/t PSA) and that the PCA3 Score had a greater diagnostic accuracy in predicting repeat biopsy outcome than the free/total PSA ratio. PCA3 had the highest diagnostic performance in men with a free/total PSA ratio > 10%
• This subanalysis of the European repeat biopsy study¹ evaluated the performance characteristics of the PCA3 Assay in predicting repeat biopsy outcome relative to the f/t PSA in 301 men with a prior negative biopsy and a PSA level 2.5-10 ng/mL. The PCA3 Score was evaluated in f/t PSA subgroups ≥ 20%, 10-20% and ≤ 10%, at cut-offs of 25, 30 and 35
• The repeat biopsy was positive in 18.8% of 117 men with a f/tPSA ≥ 20%, 23.9% of 138 men with a f/tPSA 10-20% and 34.8% in 46 men with a f/t PSA ≤ 10%
• The PCA3 Score was independent of f/t PSA: the Areas Under the Receiver Operating Characteristic curve (AUC ROC) were comparable for men with a f/t PSA of  ≥ 20%, 10-20% and ≤10% (Table). The sensitivity and specificity of the PCA3 Score was also comparable for the three different subgroups at cut-offs of 25, 30 and 35 (Table)
• In men with a f/t PSA of  ≥ 20% and 10-20%, the odds-ratio (OR) of the PCA3 Score for predicting a positive repeat biopsy ranged from 3-4.5 depending on the PCA3 Score used, which was statistically significant (P= 0.021-<0.001). In men with a f/t PSA ≤ 10%, the OR of PCA3 for predicting a positive repeat biopsy ranged from 1.6-2.9; this was not statistically significant
• PCA3 had a higher AUC ROC (0.688) compared to serum total PSA (0.553) and f/t PSA (0.571)
• In multivariate analysis (including PCA3, f/t PSA, total PSA, prostate volume, number of prior biopsies and DRE outcome), a PCA3 Score > 30 was a statistically significant predictor of a positive biopsy while serum total PSA and f/t PSA were not
• The PCA3 Score was independent of prostate volume, while the f/t PSA did depend on prostate volume
• It was concluded that in men with a prior negative biopsy and a PSA level 2.5-10 ng/mL, the PCA3 Score was strongly associated with a positive repeat biopsy. The diagnostic value of the PCA3 Score was independent of f/t PSA level and outperformed f/t PSA in predicting cancer on repeat biopsy. The highest diagnostic accuracy of the PCA3 Score was obtained in men with a f/t PSA > 10%

1) Haese A, et al. Clinical utility of the PCA3 urine assay in European men scheduled for repeat biopsy. Eur Urol 2008;54:1081-8

Editorial comment

In this paper a clinical question is addressed that comes up immediately when one is confronted with predictive value of PCA3 for biopsy outcome, i.e. how does it compare to % free PSA. Ploussard and colleagues work this issue out diligently, to show that in all ranges PCA3 has additional value, albeit that the highest accuracy is obtained in the >10 % range. Notably the majority of patients have free PSA > 10 %, so this is clinically most relevant. This is a confirmation that PCA3 can be used to reduce the number of unnecessary biopsies significantly.

More information: Article at PubMed