Prostate cancer in nonurological patients with normal prostates on digital rectal examination

Random systematic ultrasonographically guided transrectal core biopsies of the prostate were performed in 73 patients with pulmonary malignancies to exclude prostate cancer as a primary malignant neoplasm. Of the patients 41 had normal prostates as judged by digital rectal examination, 27 had firm prostates and 5 had clinical stage B nodules. Hypoechoic areas were seen on transrectal ultrasonography in 14 of the 41 patients (34%) with normal prostates. Biopsy of the hypoechoic areas in this subgroup detected only 1 grade II prostate cancer. In another patient with normal transrectal ultrasound grade I cancer was detected by mapping of the prostate with 6 systematic ultrasonographically guided transrectal core biopsies. Of the remaining 39 patients with normal prostates transrectal ultrasound detected no hypoechoic defect in 26, a specificity for the detection of prostate cancer of 67%. Multiple core biopsies revealed prostate cancer in 15 of the 32 cases of palpably abnormal prostates, including 12 that were hypoechoic. Prostate cancer is a rare histopathological finding in men with normal prostates on rectal examination. Transrectal ultrasound detected only 1 of 2 low volume prostate cancers in our study group. Thus, ultrasound seems to have little use in patients with prostates that appear normal on digital examination, and its specificity is low.