Abstract

Introduction: Cancer of the prostate is the most common male cancer in the United States. Only lung cancer causes more cancer deaths in North American men than prostate cancer. For prostate cancer detection three diagnostic modalities are available at the present. These are digital rectal examination (DRE), prostate specific antigen (PSA) and transrectal ultrasonography of the prostate (TRUS). In the present study for early detection of prostate cancer, we have investigated the usefulness of transrectal ultrasonography in patients with prostate specific antigen levels of 4.0 ng/ml or less and with normal digital rectal examination.

Materials and Methods: Between January 2000 and February 2003 we have done 121 transrectal ultrasonography guided systematic sextant prostate biopsies. If needed additional biopsies were done. The data of these patients were analyzed retrospectively. Of these 22 (18.1%) with prostate specific antigen levels of 4.0 ng/ml or less and with normal digital rectal examination were included to study. Serum prostate specific antigen levels were assed by Hybritech® (Beckman - Coulter, USA) method. Transrectal ultrasonography was performed using a Hitachi EUB-525 ultrasound scanner and a 6.5 MHz endorectal probe with the patient in the left lateral decubitis position. Abnormal transrectal ultrasonography findings were classified as capsular irregularity and hypoechoic lesions. The mean age of these patients were 61±3.2 (54-71). The patients were divided into 4 groups according to prostate specific antigen levels. The reliability of transrectal ultrasonography was investigated among these 4 groups.

Results: Of the 22 subjects, in 2 patients, prostate cancer (9.1%) and in 1 patient high grade prostatic inthraepithelial neoplasia. (PIN) (4.5%) were diagnosed. In all these patients prostate specific antigen levels were over 3.0 ng/ml. In patients with prostate specific antigen levels of 0-3 ng/ml the detection rate of prostate cancer or high grade PIN was 0%. If we did not perform biopsy to these patients (n=14), our biopsy number would be decreased from 22 to 8, and cancer detection rate would be improved (from 9.1% to 25%). And also none of the cancer or high grade prostatic intraepithelial neoplasia cases would be misdiagnosed.

Conclusion: Prostate specific antigen is the best single method for predicting prostate cancer. TRUS and TRUS guided prostate biopsy might not be undertaken in subjects with PSA levels less than 3.0 ng/ml and with normal digital rectal examination. The additional use of TRUS in subjects with PSA levels of 3-4 ng/ml would be improved the sensitivity of prostate cancer detection.