Publication
Kirby RS, Fitzpatrick JM and Irani J; BJU Int 2009;103:441-5
- Currently, the diagnosis of prostate cancer (PCa) relies on the outcome of a digital rectal examination (DRE) and serum total prostate specific antigen (PSA) levels, which may lead to a decision to perform a prostate biopsy
- However, the DRE outcome is subjective and has a low predictive value. The serum total PSA level is subject to flaws, mainly related to its non-specificity for PCa, and is also a poor indicator of the aggressiveness of PCa
- These flaws may lead to over-diagnosis and over-treatment of PCa. Complementary indicators are needed to better inform the decision to biopsy or to proceed to active therapy
- PCA3 (Prostate CAncer gene 3) is a gene-based marker that is, unlike PSA, highly specific for PCa. The Progensa® PCA3 Assay is a non-invasive test that detects the presence of PCA3 messenger RNA (mRNA) in urine. The PCA3 Score is calculated as the ratio of PCA3 and PSA mRNA. PCA3 sample collection and urine specimen stability are robust: informative rates (% of urine samples having adequate concentrations of PCA3 and PSA mRNA for calculation of PCA3 Score) are > 99%
- The PCA3 Score could be of use in several clinical scenario’s:
- To aid in first biopsy decisions in men in whom the serum total PSA levels are inconclusive (2.5-10 ng/mL)
- To aid in repeat biopsy decisions in men in whom the DRE and serum PSA levels are suspicious and/or family history and other factors indicate an increased risk of PCa
- To aid in the decision on treatment strategy (radical prostatectomy vs. active surveillance) in men with a positive biopsy in whom the aggressiveness of PCa is unknown
- Several clinical studies have consistently shown a better diagnostic accuracy for the PCA3 Score vs. serum total PSA
- The PCA3 Score, is in contrast to serum total PSA level, not associated with prostate volume
- The PCA3 Score may be associated with PCa aggressiveness. The PCA3 Score has been shown to correlate with total tumour volume and Gleason score in prostatectomy samples. In addition, the PCA3 Score was significantly higher in men with clinical stage T2, biopsy Gleason score ≥ 7, and “significant” PCa compared to men with clinical stage T1, biopsy Gleason score < 7, and “indolent” PCa. (note: indolent PCa defined as: stage T1c, PSA density < 0.15, biopsy Gleason score ≤ 6, ≤ 33% positive cores)
- The performance of the PCA3 Score is independent of serum total PSA levels
- Logistic regression analyses and the incorporation of the PCA3 Score in to the Prostate Cancer Prevention Trial (PCPT) risk calculator showed that the PCA3 Score can be combined with other factors, such as prostate volume, DRE outcome and serum total PSA level, into a nomogram to improve the prediction of PCa at biopsy
- It was concluded that the PCA3 Score supplements serum total PSA in PCa diagnosis and is insensitive to the non-specific factors that can affect serum total PSA. The addition of PCA3 to the urologist’s diagnostic tools will improve diagnostic sensitivity, specificity and predictive value. In turn, biopsy and management decisions might be better informed. This has the potential to improve the overall level of patient care
More information: Article at PubMed