Value of prostate volume measurement using transabdominal ultrasonography for the improvement of prostate-specific antigen-based cancer detection

PURPOSE: To examine value of prostate-speci fi c antigen (PSA) adjusted by prostate volume measured using transabdominal ultrasonography in prostate cancer detection among men with elevated PSA. METHODS: 238 men aged 79 years or younger with serum PSA levels of 2.0-20.0 ng/mL and normal digital rectal examination fi ndings were studied in terms of total and free PSA, prostate volumes with transrectal (TRUS) and transabdominal (TAUS) ultrasonography and transition zone volumes with TRUS prior to transrectal 10-core biopsy. In addition to sole PSA values and the free-to-total PSA ratio, volume-adjusted PSA values, PSA densities determined by TRUS (PSAD(TRUS)), and TAUS (PSAD(TAUS)), and PSA transition zone densities (PSATzD) were compared using receiver operating characteristic (ROC) analysis. RESULTS: Prostate cancer was diagnosed in 58 (24.4%) of the 238 men who underwent prostate biopsies. Of the areas under ROC curves (AUC) of studied parameters, PSATzD (AUC 0.751) was the best and signi fi cantly superior to PSAD(TAUS) (AUC 0.664, P = 0.007). However, PSAD(TAUS) exceeded PSA (AUC 0.559, P = 0.004) and showed potential capability of a one-fourth reduction in unnecessary biopsies without spoiling sensitivity (90%). Cancer detection rate was only 4.2% in the 48 patients whose prostate volume in TAUS was > 50 mL and PSAD(TAUS) was < 0.075. CONCLUSIONS: Since PSAD(TRUS) and PSATzD were signi fi cantly superior to PSAD(TAUS), TRUS is feasible as the standard fashion to determine prostate volume in the diagnosis of prostate cancers. However, TAUS is also worthwhile as it can improve the prostate cancer detection using sole PSA, and primary use of TAUS has the potential to reduce the substantial number of unnecessary biopsy safely.