[Evaluation of our series of first biopsies and rebiopsies by applying a prostate cancer risk calculator.]

Objectives: 1.- To know the risk of detectable Prostate Cancer (PC) and significant PC by applying a Risk Calculator to patients who underwent a prostate biopsy (PB) and to analyze if there are significant differences between the risk of patients who had positive versus negative biopsies. 2.- To compare the risk of those patients with positive results who were detected in the first biopsies vs re-biopsies. 3.- To compare our results with those obtained if we had applied the cut points established in the CP risk calculator.
Methods: Through a retrospective descriptive analytical study, we studied 496 prostate biopsies (PB) performed during 3 years (2014-2016), applying the SWOP risk calculator, analyzing if there are significant differences between those patients who had a positive vs negative result and those submitted to re-biopsies.
Results: The mean risk of detectable PC by the calculator for positive PB was 34.98% versus 24.71% of negative PB; in relation to the risk of significant PC, for positive PB it was 19.13% versus 8.8% of the negative PB, with significant differences (p<0.01) in both comparisons. When patients were grouped by first biopsies vs re-biopsies, we observed that patients with the first positive biopsy had an estimated risk by the calculator of 44% compared to 31% of the first negative prostate biopsies, this difference being statistically significant.
Conclusions: The application of a prostate cancer risk calculator in candidates for first biopsy allows optimization of the test, although it loses effectiveness in patients with previous negative PB.