Biopsia transrectal ecodirigida de próstata: aportación de una unidad urológica de diagnóstico ecográfico tras 10 años de experiencia

Abstract

Although transrectal ultrasound-guided (TRUS) prostatic biopsy is the procedure of choice for the diagnosis of prostate cancer (PC), neither the ideal number of cores nor the number of repeated biopsies, nor the required diagnostic yield have been established. After our experience of ten years with TRUS biopsy we perform a review of the technique and its indications. PSA, ultrasound features, and pathologic data of 6000 patients undergoing modified sextant TRUS biopsy between 1994 to December 2002 were collected. 222 patients undergoing ten-core TRUS biopsy were included in an experimental group to study the role of the extended biopsy. The contribution of the extra cores to the diagnostic yield in the experimental group was studied to determine the effectiveness of the extended biopsy, using as a control group 552 patients undergoing sextant TRUS biopsy during 2002. Both groups were comparable for the study variables at the start of the study. The incidence of PC in the first biopsy in the group of 6000 patients was 39.1% (2345/6000). Patients with PSA between 4 and 10 ng/ml have an incidence of PC greater than 50% among prostates smaller than 20 cc, diminishing down to 8.9% in those greater than 50 cc. The percentage of PC among patients with negative digital rectal examination (DRE), normal TRUS, and PSA below 4 ng/ml was 16.7%. The diagnostic yield for PSA density lower than 0.11 ng/ml/cc was lower than 8%. The free/total PSA ratio shows a 13.7% incidence of PC with values higher than 0.24. Multivariate logistic regression analysis showed that the only non-significant parameter was free/total PSA. Sixty (27.15%) patients of the extended TRUS biopsy group had PC. Only 2.25% of the 221 patients benefited from the augmented number of biopsies. There were no significant differences in the figures of prostate cancer between groups. Only PSA and volume where significant in the multivariate logistic regression analysis; number of samples, PSA density and age lacked of influence in the detection of PC. The sextant biopsy model obtaining cores from the lateral horns of the prostate continues to be the reference for TRUS biopsy, and the extended biopsy is not applicable to all patients from the beginning do to the small increase in the diagnostic yield. Isolated PSA may not be the unique reference to indicate TRUS biopsy, being volume, in our experience, a definitive factor for the adjustment of high risk levels.