DIAGNOSIS OF PROSTATIC-CARCINOMA - THE YIELD OF SERUM PROSTATE-SPECIFIC ANTIGEN, DIGITAL RECTAL EXAMINATION AND TRANSRECTAL ULTRASONOGRAPHY

Three tests are commonly used to diagnose prostate carcinoma to date: serum prostate specific antigen (PSA), digital rectal examination and transrectal ultrasonography. We evaluated these 3 tests in 1,001, 6-se ctor prostate needle biopsies to rule out prostate carcinoma. Of the b iopsies 253 (25.3%) revealed prostate cancer. As a single test, PSA wa s superior to digital rectal examination or transrectal ultrasonograph y in predicting cancer in this patient population using difference of proportions tests. Receiver operating characteristic analysis also sho wed PSA to be the superior test. The combinations of PSA plus transrec tal ultrasonography and PSA plus digital rectal examination were super ior to digital rectal examination plus transrectal ultrasonography. We found cancer in 35 of 188 patients (18.6%) with intermediate PSA leve ls of 4.1 to 10.0 ng./ml. and normal or asymmetric nonindurated rectal examinations. Only 5 of 79 patients (6.3%) with a normal digital rect al examination and PSA level of less than 4.0 ng./ml. demonstrated car cinoma on biopsy. Of the 5 patients 4 had annual increases in PSA of 4 0% or greater. While hypoechoic sectors were more than twice as likely as isoechoic sectors of the prostate to contain malignancy on biopsy, nearly 37.6% of the cancers were found in isoechoic sectors. A strate gy of performing biopsy of only hypoechoic sectors would have misdiagn osed 24.6% of the patients with prostate cancer. We conclude that seru m PSA is the most accurate of the 3 diagnostic tests evaluated. We als o recommend a systematic sextant biopsy technique.