Use of transrectal ultrasound in diagnosis, guided biopsy, staging, and screening of prostate cancer.

TRUS allows visualization of the internal anatomy of the prostate gland. Knowledge of zonal prostate anatomy allows more accurate staging of prostate cancer by use of strategic TRUS-guided biopsy of sites of possible tumor extension. These biopsies may be facilitated via the transrectal route using an automatic Biopsy system. TRUS is twice as sensitive as DRE and is capable of detecting nonpalpable prostate cancer. TRUS can detect nonpalpable tumors with average dimensions as small as 1.0 cm. This size is considered to be clinically significant.