[Outcomes of expanded use of PCA3 testing in a Spanish population with clinical suspicion of prostate cancer]. / Resultados del uso expandido del PCA3 score en una población española con sospecha de cáncer de próstata.

ABSTRACT

OBJECTIVES: DD3(PCA3) (PCA3) gene expression is prostate cancer-specific. Routine use of this biomarker has resulted in a 35-67% reduction in the number of required biopsies. The aim of this study is to evaluate our outcomes in its routine use and to establish in which group of patients this is the most efficient, depending on the number of previous PCA3 biopsies. MATERIAL AND METHODS: A total of 474 consecutive patients who had previously undergone a biopsy (group A, n=337) or not (group B, n=134) for whom a PCA3 was requested were analyzed. We subdivided group A into A(1) (a previous biopsy, n=182) and A(2) (<1 previous biopsy, n=155). The recommendation of whether to perform a biopsy or not was made independently by each of the 11 clinicians and guided by prostatic specific antigen (PSA) levels and digital rectal examination. RESULTS: Median age was 65 years (range 38 to 84). PCA3 score had an informative ratio of 99.6%, with a median of 29 (range 1-3245). The percentage of biopsy sparing was 49% of the cases. ROC analysis demonstrated an AUC for PSA and PCA3 of 0.532 (P=.417) and 0.672 (P<.0001), respectively. Sensitivities of PSA≥ 4 and PCA3≥ 35 were 87% vs. 85%, with specificities of 12% vs. 33%, PPV 34% vs. 39% and NPV 63% vs. 81%, respectively. The PCA3 score showed direct correlation with the percentage of positive biopsies (P<.0001). CONCLUSIONS: Routine use of PCA3, due to its high NPV, results in a significant reduction in the number of biopsies. PCA3 appears to be more efficient in biopsy-naive patients. Among patients already biopsied, the results are superior in those biopsied only once.