Ornstein D K, Rao G S, Smith D S, Ratliff T L, Basler J W, Catalona W J
Division of Urologic Surgery, Washington University School of Medicine, St. Louis Missouri, USA.
J Urol. 1997 Jan;157(1):195-8.
We determined the effect of digital rectal examination and prostatic biopsy on serum total and free prostate specific antigen (PSA) concentrations in men undergoing screening for prostate cancer.
In 93 men recruited from our PSA screening program we measured the serum concentrations of total and free PSA on 3 occasions during a 30-day interval before performing digital rectal examination. Total and free PSA measurements were repeated 1 and 24 hours after the rectal examination. Serum total and free PSA also was measured immediately before, and 1 hour, 24 hours and 1 week after prostatic biopsy in 30 men.
Biological variation for total and free PSA was 14.7 and 14.0%, respectively. At 1 hour after rectal examination total and free PSA increased by more than the biological variation in 31 and 48% of the men, respectively. Increases were significantly greater in men whose initial PSA concentrations were less than 4.0 ng./ml. There was a dramatic increase in total and percentage of free PSA in all men 1 hour after prostatic biopsy. Increases in percentage of free PSA were greater in men whose biopsies revealed cancer. Total PSA remained elevated for at least 1 week in most men, while percentage of free PSA returned to within or less than the biological variation of the baseline level in 90% of the men by 24 hours.
Digital rectal examination causes a modest increase in total and percentage of free PSA. Prostate needle biopsy causes more dramatic increases in both forms of PSA. Free PSA is preferentially released into the serum after prostatic manipulation and appears to be cleared more rapidly than complexed PSA. The differential return of the different PSA forms to baseline levels after biopsy could affect the use of measurements of the percentage of free PSA in clinical practice.
我们确定了直肠指检和前列腺活检对接受前列腺癌筛查男性血清总前列腺特异性抗原（PSA）和游离PSA浓度的影响。
从我们的PSA筛查项目中招募了93名男性，在进行直肠指检前的30天间隔内，分3次测量他们血清总PSA和游离PSA的浓度。直肠指检后1小时和24小时重复测量总PSA和游离PSA。对30名男性在前列腺活检前即刻、活检后1小时、24小时和1周测量血清总PSA和游离PSA。
总PSA和游离PSA的生物学变异分别为14.7%和14.0%。直肠指检后1小时，分别有31%和48%的男性总PSA和游离PSA升高超过生物学变异。初始PSA浓度低于4.0 ng/ml的男性升高更为显著。前列腺活检后1小时，所有男性的总PSA和游离PSA百分比均急剧增加。活检发现癌症的男性游离PSA百分比增加更大。大多数男性的总PSA至少升高1周，而90%的男性游离PSA百分比在24小时内恢复到基线水平的生物学变异范围内或以下。
直肠指检导致总PSA和游离PSA百分比适度增加。前列腺穿刺活检导致两种形式的PSA都有更显著的增加。前列腺操作后游离PSA优先释放入血清，且清除速度似乎比结合型PSA更快。活检后不同PSA形式恢复到基线水平的差异可能会影响临床实践中游离PSA百分比测量的应用。
