前立腺再生検の検討:特にMRIの有用性について

Abstract

初回の前立腺生検が陰性であった51例に対し再生検を計59回行い, 再生検病理結果と各種パラメーターや画像所見を比較検討した.再生検の結果, 26例(44.6%)が癌陽性であった.癌陽性群は癌陰性群と比べ, 有意に年齢が高く, 前立腺体積が小さく, PSA-Dが高い傾向にあった.DRE・TRUSおよびMRIの臨床・画像所見と再生検結果との関係では, DRE・TRUSともにaccuracyは61～62%に対し, MRIではaccuracyが69.4%と有意に高値を示し, NPVは78.9%であった.特にサンプリングエラーを疑い1年以内に再生検を行った症例では, MRIのaccuracyは80.8%, NPV 100%ときわめて良好な結果であった

Among patients with negative initial biopsies of the prostate, 51 patients underwent total 59 repeat biopsies at the Department of Urology of Ikeda Municipal Hospital between January 1998 and April 2004. Overall 26 patients (44.1%) were confirmed to have cancer, 22 patients by second repeat biopsy (22/51), four patients by third biopsy (4/7) and none by fourth biopsy (0/1). Clinical parameters (age, PSA, PSA density, PSA velocity) were analyzed for the possibility to predict the pathological outcome. Significant differences between the positive biopsy group and the negative biopsy group were obtained in age, PSA level and prostatic volume. Of the diagnostic evaluations including palpation and imaging studies (DRE, TRUS, MRI), the most powerful predictor for prostate cancer seemed to be the MRI findings, especially in the cases of short-interval repeat biopsy. Biopsies directed at the positive lesion on MRI in addition to systematic prostate biopsies should be useful.