Presti J C, Hovey R, Carroll P R, Shinohara K
Department of Urology, University of California School of Medicine, San Francisco Veterans Administration Medical Center, USA.
J Urol. 1996 Nov;156(5):1685-90.
We evaluated prospectively prostate specific antigen (PSA) and prostate specific antigen density in the detection of prostate cancer in patients with normal findings on digital rectal examination with and without normal transrectal ultrasound.
Consecutive patients (184) with an elevated serum PSA and normal digital rectal examination underwent transrectal ultrasound with lesion directed and systematic biopsies (6 if prostatic volume was 50 cc or less and 12 if volume was more than 50 cc). Receiver operating characteristic curves, predictive values and likelihood ratios were calculated for PSA and PSA density.
Of the 184 patients 50 (27%) with a normal digital rectal examination had cancer compared to 30 of 112 (27%) with a normal digital rectal examination and transrectal ultrasound. Median PSA or PSA density did not differ between the positive and negative biopsy groups among patients with a normal digital rectal examination (8.4 versus 7.1 and 0.22 versus 0.14 ng./ml., respectively) or a normal digital rectal examination and transrectal ultrasound (8.2 versus 7.5 and 0.21 versus 0.14 ng./ml., respectively). PSA density was superior to PSA by receiver operating characteristic analysis for cancer detection when all PSA values or those between 4 and 20 ng./ml. were considered. However, the significance was lost for a PSA of 4 to 10 ng./ml. Likelihood ratios demonstrated insignificant changes in the post-test probability if PSA density was used to determine the need for biopsy and many cancers would have been missed.
PSA density should not be used to determine the need for biopsy in patients with a normal digital rectal examination and/or transrectal ultrasound.
我们前瞻性地评估了前列腺特异性抗原（PSA）和前列腺特异性抗原密度在直肠指检结果正常且经直肠超声检查正常或异常的患者中检测前列腺癌的情况。
连续纳入184例血清PSA升高且直肠指检正常的患者，进行经直肠超声检查，并针对病变部位及系统性活检（如果前列腺体积为50立方厘米或更小，则活检6针；如果体积超过50立方厘米，则活检12针）。计算PSA和PSA密度的受试者工作特征曲线、预测值和似然比。
184例患者中，50例（27%）直肠指检正常的患者患有癌症，而112例直肠指检正常且经直肠超声检查正常的患者中有30例（27%）患有癌症。直肠指检正常的患者中，活检阳性组和阴性组之间的PSA中位数或PSA密度无差异（分别为8.4对7.1以及0.22对0.14纳克/毫升），直肠指检正常且经直肠超声检查正常的患者中也是如此（分别为8.2对7.5以及0.21对0.14纳克/毫升）。当考虑所有PSA值或4至20纳克/毫升之间的值时，通过受试者工作特征分析，PSA密度在检测癌症方面优于PSA。然而，对于4至10纳克/毫升的PSA，这种差异不再显著。似然比表明，如果使用PSA密度来确定是否需要活检，检测后概率的变化不显著，并且会漏诊许多癌症。
对于直肠指检正常和/或经直肠超声检查正常的患者，不应使用PSA密度来确定是否需要活检。
