PCA3 score and prostate cancer diagnosis at repeated saturation biopsy. Which cut-off: 20 or 35?

PURPOSE: To compare PCA3 score cut-off of 35 vs 20 in PCa diagnosis in patients undergoing repeated saturation prostate biopsy (SPBx).

MATERIAL AND METHODS: From January 2010 to May 2011, 118 patients (median 62.5 years) with primary negative extended biopsy underwent a transperineal SPBx (median 30 cores) for persistent suspicion of PCa. The indications for repeated biopsy were: persistently high or increasing PSA values; PSA > 10 ng/mL, PSA values between 4.1-10 or 2.6-4 ng/mL with free/total PSA ≤ 25% and ≤ 20 %, respectively; moreover, before performing SPBx urinary PCA3 score was evaluated.

RESULTS: All patients had negative DRE and median PSA was 8.5 ng/mL (range: 3.7-24 ng/mL). A T1c PCa was found in 32 patients (27.1 %): PCA3 score was 59 (median; range: 7-201) in the presence of PCa and 35 (median; range: 3-253) in the absence of cancer (p < 0.05). In the presence of ASAP and HGPIN median PCA3 score was 109 (range: 42-253) and 40 (range: 30-140), respectively. Diagnostic accuracy, sensitivity, specificity, PPV and NPV of PCA3 score cut-off of 20 vs 35 in PCa diagnosis were 44.9 vs 50 %, 90.6 vs 71.9 %, 27.9 vs 41.8 %, 31.9 vs 31.5 % and 88.9 vs 80 %, respectively. ROC analysis demonstrated an AUC for PCA3 ≥ 20 vs ≥ 35 of 0.678 and 0.634, respectively.

CONCLUSIONS: Our data suggest that PCA3 is more useful as an exclusion tool; moreover, setting a PCA3 cut-off at 20 vs 35, would have avoided 22.9 vs 38.1 % of biopsies while missing 9.4 % and 28 % diagnosis of PCa.