The significance of prostate-specific antigen alpha-1-antichymotrypsin complex and its indices for the detection of prostate cancer

Abstract

対象は1999年7月から28ヵ月間に超音波ガイド下経直腸的前立腺生検を施行したPSA2.0～10.0ng/mlの151例で, PSA, PSA-ACT, PSAD, PSATZD, PSA-ACTD, PSA-ACTTZDを測定し, ROC解析を用いてこれらのパラメーターを検討した.系統的6ヶ所生検にて151例中36例から前立腺癌が検出された.ROC解析ではPSA-ACTTZDのAUCが最大となり, PSA-ACTTZDは有意差をもってPSA単独より有用な指標と考えられた.PSA-ACTTZDのカットオフ値を0.20ng/ml2を設定することにより, 感度90%, 特異度55%で不必要な生検を回避できる可能性が示唆された

We examined the usefulness of prostate specific antigen alph-1-antichymotrypsin complex (PSA-ACT) and its indices for the detection of prostate cancer in patients with a prostate specific antigen (PSA) level between 2.1 and 10.0 ng/ml. Between July 1999 and October 2001, 151 patients with a PSA level between 2.1 and 10.0 ng/ml underwent a systematic biopsy under transrectal ultrasound (TRUS) guidance. The clinical values of total PSA, PSA-ACT, PSA density (PSAD), PSA-ACT density (PSA-ACTD), PSA transition zone density (PSATZD) and PSA-ACT transition zone density (PSA-ACTTZD) for the detection of prostate cancer were compared by using receiver operating characteristic (ROC) curve analysis. Of the 151 patients, 36 (23.8%) were histologically confirmed as having prostate cancer. The differences between patients with prostate cancer and benign prostatic disease were significant with respect to the PSA and PSA-ACT related parameters examined in this study. According to ROC curve analysis, the area under the curve (AUC) of PSA-ACTTZD was the greatest of all the parameters. The differences was significant between the AUC of PSA-ACTTZD and total PSA (p < 0.05). The cutoff value of PSA-ACTTZD with 0.20 ng/ml2 showed the highest sum of sensivitity (90%) and specificity (55%). Also, in 86 patients with a PSA level between 2.1 and 6.0 ng/ml, the AUC of PSA-ACTTZD was the greatest of all the parameters. Measuring the level of PSA-ACT and its indices may provide a better differentiation of prostate cancer and benign prostatic disease than total PSA alone in patients with intermediate PSA levels. PSA-ACTTZD is the most useful indicator among PSA-ACT and its volume indices.