Use of PCA3 in active surveillance
As a future application, PCA3 may allow clinicians to distinguish between patients with indolent and aggressive PCa who are under consideration for active surveillance (AS) protocols. While evidence suggests that PCA3 may accurately predict low-volume, clinically insignificant cancers, a number of studies have found that PCA3 alone is not a robust predictor of locally advanced disease or aggressive tumors.32,34,36
However, Lin et al.47 recently examined the correlation of PCA3 and TMPRSS2:ERG scores with higher cancer grade and volume at the time of biopsy in a cohort of 387 men on AS. They reported a sequential increase in the scores as tumor volume increased. For a negative repeat biopsy and 1%-10% and 34% or more positive cores, the median PCA3 scores were 27, 28, and 46 (P = 0.004), and median TMPRSS2:ERG scores were 3, 10, and 27 (P < 0.0001), respectively.
Despite these promising results, the role of PCA3 in the prediction of adverse tumor features as well as risk assessment in patients considering active surveillance requires further study.
Biomarkers have been targeted to best achieve the elusive goal of matching intensity of treatment to individual tumor biology. Following the controversial decision by the USPSTF, there is a clear need for improved diagnostic and prognostic tests to individualize PCa management.
Although several biomarkers show promise, PCA3 has garnered substantial attention following FDA approval and its role in the diagnosis of PCa will continue to grow in the future. Examining the current body of evidence suggests that PCA3 should not replace PSA for PCa screening, but may serve as a useful adjunct to PSA, DRE, and clinical judgment to help avoid unnecessary biopsies and identify patients with clinically significant disease who may benefit from active treatment.
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