Chybowski F M, Bergstralh E J, Oesterling J E
Department of Urology, Mayo Clinic, Rochester, Minnesota 55095.
J Urol. 1992 Jul;148(1):83-6. doi: 10.1016/s0022-5347(17)36517-5.
To determine the effect of digital rectal examination on the serum prostate specific antigen (PSA) concentration a prospective, randomized, controlled trial involving 143 patients was conducted. Of the patients 86 (60%) had benign prostatic hyperplasia (BPH), 47 (33%) had prostate cancer and 10 (7%) had chronic prostatitis. The study group consisted of 71 men, all of whom had a serum PSA determination followed by a digital rectal examination and then a second serum PSA determination. The control cohort consisted of 72 men, all of whom had 2 serum PSA determinations without an intervening digital rectal examination. The median change in the serum PSA level for the study group was 0.4 ng./ml. compared to -0.1 ng./ml. for the control cohort (p less than 0.0001). For 76% of the study patients the second serum PSA level was greater than the initial value; only 32% of the control patients exhibited a higher second serum PSA level than the initial level (p less than 0.0001). However, only 4 patients with an initial PSA value in the reference range (0.0 to 4.0 ng./ml.) had a post-digital rectal examination value greater than 4.0 ng./ml. and only 1 patient whose presenting serum value was less than 10.0 ng./ml. had a serum PSA level greater than this cutoff point after digital rectal examination. This minimal change in serum PSA after digital rectal examination was independent of the diagnosis (BPH, cancer or chronic prostatitis), initial serum PSA concentration and examiner. Thus, although digital rectal examination had a statistically significant effect on the serum PSA concentration, the clinical significance of a 0.4 ng./ml. median increase appears inconsequential. Based on these findings, physicians should be confident that the serum PSA concentration in the immediate post-digital rectal examination period is accurate and does not compromise clinical use of the tumor marker.
为了确定直肠指检对血清前列腺特异性抗原（PSA）浓度的影响，开展了一项涉及143例患者的前瞻性、随机、对照试验。这些患者中，86例（60%）患有良性前列腺增生（BPH），47例（33%）患有前列腺癌，10例（7%）患有慢性前列腺炎。研究组由71名男性组成，他们均先进行血清PSA测定，随后接受直肠指检，然后再次进行血清PSA测定。对照组由72名男性组成，他们均进行2次血清PSA测定，期间未进行直肠指检。研究组血清PSA水平的中位数变化为0.4 ng/ml，而对照组为-0.1 ng/ml（p<0.0001）。76%的研究患者第二次血清PSA水平高于初始值；只有32%的对照患者第二次血清PSA水平高于初始水平（p<0.0001）。然而，初始PSA值在参考范围（0.0至4.0 ng/ml）内的患者中，只有4例直肠指检后的PSA值大于4.0 ng/ml，而初始血清值低于10.0 ng/ml的患者中，只有1例在直肠指检后血清PSA水平高于该临界值。直肠指检后血清PSA的这种微小变化与诊断（BPH、癌症或慢性前列腺炎）、初始血清PSA浓度及检查者无关。因此，尽管直肠指检对血清PSA浓度有统计学上的显著影响，但中位数增加0.4 ng/ml的临床意义似乎不大。基于这些发现，医生应确信直肠指检后即刻的血清PSA浓度是准确的，不会影响该肿瘤标志物的临床应用。
