Validity of Transrectal Ultrasonography in the Early Diagnosis and Staging of Prostatic Cancer

Abstract

In 3 years of mass screening for early diagnosis of prostatic cancer, 57 tumors were found (57/5000, for a detection rate of 1.2%). Patients first underwent digital rectal examination (DRE): at present the least expensive, least invasive and most effective way to diagnose prostatic cancer. 420 men underwent transrectal ultrasonography (TRUS) with a 5 MHz transverse and longitudinal transducer for pathological digital rectal findings, obstructive symptoms and other reasons. Prostatic biopsy was performed in 190 patients with DRE findings and/or hypoechoic zones of the prostatic gland (transrectal digitally directed or ultrasonically perineal guided biopsies). The specificity, sensitivity and prediction capacity of DRE and TRUS in this group of patients was evaluated. Sensitivity of DRE was 92%, specificity 42% (usual finding for mass screening); predictive positive value was 41 %, negative 93%. Sensitivity of TRUS was 77%, specificity 57%, predictive positive value was 44%, negative 86%. Data seem to confirm the ability of TRUS to reduce the number of “false positives” after DRE (and consequently the number of biopsies). However, contraindications for use in mass screenings are: sensitivity lower than with DRE, high false positive rate and prohibitive cost for systematic use. Validity of TRUS is confirmed in clinical staging for the selection of patients undergoing radical retropubic prostatectomy, by comparison with local pathological staging.