Department of Urology, Faculty of Medicine, University of Tokyo
Prostatic cancer, Cancer staging, Transrectal sonography, Digital examination
In recent years, the incidence of prostatic cancer has been gradually increasing in Japan. For appropriate therapy and prognosis, accurate staging of cancer is essential. Evaluation of cancer staging by digital examination, ultrasonography, CT and MRI have been reported. Among these modalities, ultrasonography is thought to be the most valuable in the demonstration of local extension of cancer. In this study, 91 patients with prostatic cancer examined by transrectal sonograms were reviewed retrospectively and staged into localized and infiltrating cancer. Tumor infiltration by ultrasonography was judged according to three criteria: (1) irregular contour of prostate, (2) marked deformity and (3) seminal vesicle infiltration. Thirty three cases were diagnosed as localized cancer (stage T1 or T2) and 58 cases were diagnosed as infiltrating cancer (stage T3). On the other hand, by digital examination, 50 cases were judged as localized cancer (stage T1 or T2) and 41 cases were judged as infiltrating cancer (Stage T3). Stages by ultrasonography were agreed with digital examination in 66 cases of 91 (72.5%). Twenty one cases (23%) judged as infiltrating cancer by ultrasonography were judged localized cancer by digital examination. In most of these cases, ultrasonography demonstrated irregular contours at the anterior surface of the prostate and/or the marked deformity of the whole prostatic shape. These were not detectable by digital examination. Ultrasonography is more valuable than digital rectal examination in prostatic cancer staging.