限局性前立腺癌の診断と治療における超音波ガイド下前立腺生検の有用性

Abstract

1991年より下部尿路症状を有する中高年男子に, 経直腸的超音波ガイド下での前立腺生検を行った.超音波ガイド下生検は血清PSA測定と組み合わせることで限局性前立腺癌の診断に非常に有用であった

Recently the ultrasound-guided prostate biopsy, especially random systematic biopsy, is considered more sensitive than the usual site-directed biopsy for the detection of localized prostate cancers. To confirm the usefulness of the ultrasound-guided prostate biopsy in the diagnosis and treatment of prostate cancer, we analyzed 170 cases who underwent ultrasound-guided prostate biopsy due to the abnormal findings in digital rectal examination (DRE), transrectal ultrasonography (TRUS) or serum level of prostate specific antigen (PSA). Prostate cancer was detected in 53 patients including 25 patients with metastatic lesions. Excluding the advanced prostate cancers, the positive predictive value (PPV) of DRE, TRUS and serum PSA was 3.8, 8.1, and 20.8%, respectively, when only one category showed abnormal finding in spite of normal finding of the others. Although these values were very low, it seemed necessary to apply all three tests for the detection of localized prostate cancer because the prostate biopsy was indicated by the abnormal finding of a single category in 9 cases (32%; 6/28) with localized cancers. The PPV of hypoechonic region on ultrasonography was 36%, and no cancer was demonstrated in the hypoechoic region at the transition zone, suggesting a low specificity of the hypoechoic region. Although there was no statistical association between the clinical stage and the number of positive cores or the length of cancerous tissue in the sextant biopsies, 64% of coincidence was observed between Gleason's sum of biopsy cores and that of operative specimens.