[Prostate cancer diagnosis using 24 cores extended biopsy]

To determine the diagnostic performance of extended prostatic biopsy (PB) in prostate cancer (PC) and variables affecting positivity.

Patients (n = 147) underwent 24 cylinder PB at the Arquitecto Marcide Hospital, Ferrol, La Coruña, between December 2002-September 2004. Inclusion criteria were the following: patients aged < or = 70 with one or more negative PB or aged < or = 75 with two or more negative PB. An univariate analysis was carried out using the chi-squared test for the qualitative variables and the t-Student and U Mann-Whitney tests in the case of the quantitative variables, plus a logistical regression analysis in order to identify those variables related to the extended PB positivity.

60 patients (40.82%) were identified as having PC. Significant differences were observed in prostatic volume, free/total PSA ratio in the initial PB, free/total PSA ratio in the extended PB, PSA-density in the extended PB as well as the existence of chronic prostatitis in previous PB. During the multivariate analysis it was found that the PSA-density and the presence of chronic prostatitis in previous PB independently predicted the positivity of the extended PB.

Extended PB allows for the detection of PC in 40.82% of patients with previous negative PB. The increase in PSA density is associated with a greater probability of PC, whilst the existence of chronic prostatitis in prior PB significantly reduces the probability of PC in the extended PB.