Prostate-specific antigen値(Tandem-R)に基づいたSystematic biopsyの適応

Abstract

1)systematic biopsyを80例施行し, 重篤な合併症はなかったが, 1例の前立腺癌を見逃した. 2)前立腺特異抗原(PSA)のpositive predictive valueは4.0ng/ml以下で33.3%, 4.1～10.0ng/mlで23.3%, 10.1～20.0ng/mlで50.0%, 20.0ng/mlを越える症例で78.9%(10.1ng/ml以上では63.6%)であり, 欧米の報告と同様の結果であった. 3)systematic biopsyの適応はPSA値のgray zoneにおいて, digital rectal examinationやPSAのみで決定するよりも, 経直腸的超音波断層法やPSA densityを併用すれば不必要な生検を避け得る可能性が示唆された

Between August 1995 and June 1996, a total of eighty Japanese men underwent ultrasound guided systematic biopsy of the prostate. Sixty-six men were clinically suspected of having prostatic cancer by elevated serum PSA (Tandem-R kit) value or digital rectal examination (DRE). Overall, 63 of the 80 (78.8%) men had elevated serum PSA with normal DRE and 30 of the 80 men (37.5%) had prostatic cancer. In patients with PSA values of 0 to 4.0 ng/ml, 4.1 to 10.0 ng/ml and 10.1 ng/ml or more, the positive predictive value of PSA was 33.3%, 23.3% and 66.7%, respectively. In patients with PSA levels of 4.1-10.0 ng/ml, the positive predictive values of digital rectal examination, transrectal ultrasonography and PSA density were 30.0%, 28.0% and 31.8%, and the false-negative rates were 20.0%, 0% and 0%, respectively. Along with the findings of transrectal ultrasonography and PSA density, estimation of PSA value and abnormal findings of digital rectal examination may help minimize the number of biopsies in patients with PSA values of 4.1-10.0 ng/ml. Systematic biopsies were performed without major complications. The biopsy missed the cancer in 4.6%.