Chemiluminescence Immunoassay PSA(ACS-PSA)を中心とした前立腺癌診断についての臨床的検討

Abstract

1)Prostate systematic biopsyを施行した147例中61例に, TUR-Pを施行した96例中2例に前立腺癌を認め, ACS-PSAとの関係を検討した. 2)ACS-PSAは感度は良好だが, 特異性が低いため, 正診率は低い.経腹的超音波(TAUS)により算出したPSAD(A)では, 感度を下げることなく特異性と正診率が向上した. 3)PSA<3.0ng/mlに5例の癌を認め, いずれもDRE所見(+).3.0≦PSA<15.0ng/mlの範囲ではbiopsyで9例, TUR-Pで2例の癌が認められた.これら11例は全てPSA>6.0ng/ml, PSAD(A)>0.3ng/ml/cm3. 4)PSAD(A)の0.5ng/ml/cm3をcut off値として用いた場合, PSAの低い領域を含む広い範囲において感度を90%程度以上に維持し, また特異性や正診率が最も高く, 最も実用的な数値と考えられた

Serum prostate specific antigen (PSA) levels were measured using an ACS-PSA kit in 147 systematic biopsy cases (61 with prostate cancer (PC)) and 96 transurethral resection of prostate (TUR-P) cases (2 with PC). In the 147 biopsy cases, the sensitivity for PSA using 3.0 and 10.0 ng/ml as cut-off values was 91.8 and 90.2%, while the specificity was 9.30 and 30.2%, respectively. The sensitivity for PSAD (A) (calculated by transabdominal ultrasound) using 0.25 and 0.5 ng/ml/cm3 as cut-off values was 91.8 and 90.2%, while the specificity was 22.1 and 50.0%, respectively. These data indicated that PSAD (A) provided better information for detecting PC than PSA alone. No statistical difference was found between PSAD (A) and PSAD (R) (calculated by transrectal ultrasound) in the utility of detecting PC. PSA below 15.0 ng/ml was seen in sixteen patients with PC. Five of these sixteen patients had a PSA level of 0.3 ng/ml/cm3. In all 243 cases, PC was not found in the 49 patients (PSA < 3.0 ng/ml) or 91 patients (PSAD (A) < 0.25 ng/ml/cm3) who had no abnormal findings by DRE and transabdominal ultrasonography. These results suggested a criterion in the use of the ACS-PSA kit for the indication of prostate biopsy and TUR-P.