The evaluation of prostatic cancer: transrectal ultrasonography of prostate, digital rectal examination and serum PSA

Kang, Soon Gu; Sul, Chong Koo

Abstract

Prostatic cancer is a pervasive disease affecting a large percentage of men over the age of 50. In those cases where the malignancy is localized to the prostatic gland, digital rectal examination (DRE), the traditional diagnostic method for prostatic cancer, may not be diagnostic. It is also well recognized that although small nodular indurated areas in the prostate may be readily palpable the differentiation between benign and malignant area cannot be made reliably by digital rectal examination alone. Various techniques have been used to detect the prostatic cancer. But there are many problems for routine use. So in order to evaluate the diagnostic modalities for prostatic cancer such as DRE, serum PSA assay and transrectal ultrasonography (TRUS) according to histopathologic results, three diagnostic modalities (DRE, serum PSA assay and TRUS) were performed in 51 cases of 140 cases with prostatism in the Department of Urology, Chungnam National University Hospital from January. 1989 to November, 1990. The results were as follows: 1. In 140 patients with prostatism, 1O3 cases were benign prostatic hyperplasia, and 37 cases(23.6%) were prostatic cancer, which was increased with aging in its frequency. 2. In TRUS, serum PSA assay and DRE, diagnostic results for prostatic cancer were 93.3%, 73.3% and 60.0% in sensitivity, 91.7%, 88.9% and 86.1% in specificity, 82.4%, 73.3% and 64.3% in positive predictive value, 97.1%, 88.9% and 83.8% in negative predictive value, and 27.5%, 21 6% and 17.6% in detection rate, respectively. 3. The risk of malignancy is increased with high positive rate in TRUS, DRE and serum PSA. So, diagnostic error would be minimized, if more diagnostic modalities are used with combination than alone.