游离PSA与总PSA比值在前列腺癌鉴别诊断中的意义

目的　探讨游离前列腺特异性抗原 (fPSA)与总前列腺特异性抗原 (tPSA)比值 (f tPSA)在tPSA为 4～ 10ng ml时对前列腺癌和良性前列腺增生 (BPH)鉴别的意义及其局限性。方法　对1998年 10月至 2 0 0 2年 10月接受诊治的 180例血清tPSA为 4～ 10ng ml的前列腺癌和BPH患者进行回顾性分析。经组织学证实 ,36例 (2 0 % )是前列腺癌 ,14 4例 (80 % )是BPH。血清中tPSA和fPSA通过酶免微粒子捕捉法测定。前列腺体积通过经腹壁超声测定。前列腺癌与BPH组间比较用t检验。采用Pearson相关系数分析前列腺体积与f tPSA之间的相关性。结果　前列腺癌患者的tPSA、f tPSA平均值分别是 6 75ng ml与 0 17;BPH患者则是 6 4 8ng ml和 0 2 5。两组患者的tPSA差异无显著意义 (P >0 0 5 ) ,而前列腺癌患者的f tPSA值显著低于BPH患者 (P <0 0 1)。此外 ,两组患者的前列腺体积与f tPSA均呈显著正相关 (前列腺癌组相关系数r=0 5 0 ,P <0 0 1;BPH组r=0 2 4 ,P <0 0 1)。在前列腺体积小于 4 0cm3,两组患者的f tPSA差异有显著意义 (P <0 0 5 ) ,当体积超过 4 0cm3,则差异无显著意义 (P >0 0 5 )。结论　f tPSA对tPSA在 4～ 10ng ml之间的前列腺癌和BPH的鉴别诊断有重要意义 ,但由于受前列腺体积的影响 ,只有在

Significance and limitations of f/tPSA in differential diagnosis of prostate cancer with tPSA levels between 4 and 10 ng/ml

OBJECTIVE: To study significance and limitations of the ratio of free to total prostate specific antigen (f/t PSA) in differential diagnosis between prostate cancer and benign prostatehyperplasia (BPH) with total PSA (tPSA) levels between 4 and 10 ng/ml. METHODS: We analysed retrospectively 180 prostate cancer and BPH patients who were diagnosed and treated in our hospital from October 1998 to October 2002 and had serum tPSA levels between 4 and 10 ng/ml. Of the 180 patients, 36 (20%) were histologically confirmed as prostate cancer and 144 (80%) BPH. The tPSA and free PSA (fPSA) in serum were measured by micropartical enzyme immunoassay. Prostate volume was measured by transabdominal ultrasonography. We chose Student's t-test for comparison between prostate cancer and BPH groups. The correlation between prostate volume and f/t PSA was analyzed using Pearson's correlation coefficient. RESULTS: The mean values of tPSA and f/t PSA were 6.75 ng/ml and 0.17 in patients with prostate cancer, 6.48 ng/ml and 0.25 in patients with BPH. The mean value of tPSA wasn't significantly different between patients with prostate cancer and BPH (P > 0.05). However, the mean value of f/t PSA of patients with prostate cancer was significantly lower than that of patients with BPH (P < 0.01). Furthermore, there were significant and positive correlation between prostate volume and f/t PSA in both groups with prostate cancer and BPH (prostate cancer group's correlation coefficient (r = 0.50, P < 0.01); BPH group (r = 0.24, P < 0.01). There was significant difference in f/t PSA between prostate cancer and BPH patients with prostate volumes more than 40 cm(3) (P < 0.05), but not between these two groups with prostate volumes more than 40 cm(3) (P > 0.05). CONCLUSION: The f/t PSA is significant in differential diagnosis between prostate cancer and BPH with tPSA levels between 4 and 10 ng/ml. But prostate volume has an effect on f/tPSA. The f/tPSA has diagnostic value of differentiation only when the prostate volume is less than 40 cm(3).