新技术让生物标志物PSA更精准检测前列腺癌
组合疗法能检测难于诊断的前列腺癌
前列腺特异抗原（PSA）的检测是否有价值引起激烈的讨论，它可能引起过度诊断的不良后果，因此，美国课题小组不推荐使用。然而，近期一项研究发表在《泌尿外科》Urology杂志上称，结合PSA生物标志物的组合药物疗法能够提高检测精度，尤其是男性患有的那些难于诊断的疾病；如果排除PSA的检测，肿瘤或许被漏诊。
在前列腺活组织检测中呈现阴性，一些男性却有很高的或反复波动的PSA水平，他们无法摆脱重复活组织检查的痛苦和不便，以排除前列腺癌的担忧或发现可能患有恶性疾病的病人。
为了提高这一检测水平，威尔康乃尔医学院的团队让276位男性每天服用5-α-还原酶抑制剂finasteride 或dutasteride（这2种药都用来缩减前列腺癌体积），在第一阶段，在6个月和12个月，研究人员对约三分之一的男性检测PSA，以及在12个月活组织检测他们的前列腺；在第二阶段，其他三分之二的男性，如果PSA水平发生改变，将接受活组织检测。
在第一阶段，药物治疗降低所用男性的PSA水平，不过降幅较大的是良性疾病而非恶性疾病。在第二阶段，约四分之一的男性接受了活组织检测，其中一半以上患有癌症。在癌症患者中，77％的病人具有危害程度最低的肿瘤。
从结果来看，研究人员推论：当PSA用于药物治疗时，它是前列腺癌的一个更有效的标记分子；他们能辨别难于诊断的良性前列腺癌患者，也许是因为活组织检测是一种检测小型肿瘤的更有效方法。在第二阶段的结论表明，仅那些不需要活组织检测的男性没有出现肿瘤。
首席研究员Steven A. Kaplan博士说：“在PSA实用性引起越来越多辩论之际，我们研究表明，在一种特定方法下，它体现出巨大价值以识别之前未曾发现的前列腺癌。”
Prostate Biopsy in Response to a Change in Nadir Prostate Specific Antigen of 0.4 ng/ml after Treatment with 5α-Reductase Inhibitors Markedly Enhances the Detection Rate of Prostate Cancer
Steven A. Kaplan , Richard K. Lee , Doreen E. Chung , Alexis E. Te , Douglas S. Scherr , Ash Tewari , E. Darracott Vaughan
Purpose We examined the effect of 5α-reductase inhibitor therapy on prostate cancer detection in men with persistently increased or fluctuating prostate specific antigen and prior negative prostate cancer biopsy.
Materials and Methods A total of 276 men with prostate specific antigen greater than 4 ng/ml (208) or a prostate specific antigen velocity change of 0.75 ng/ml (68) and a normal digital rectal examination who had previously undergone biopsy a minimum of 2 times with prostate cancer not detected were given 5 mg finasteride (154) or dutasteride (122) daily. In phase 1, 97 patients had prostate specific antigen measured at 6 and 12 months with repeat transrectal ultrasonography and biopsy (12 cores) performed at 1 year. In phase 2, 179 patients underwent biopsy triggered by a change in nadir prostate specific antigen of more than 0.4 ng/ml.
Results In phase 1 at 1 year prostate specific antigen had decreased by 2.4 ng/ml (−46.7%), and prostate volume had decreased 7.1 ml (−17.9%). Prostate cancer was detected in 27 of 97 (27.8%) patients and the mean minimum prostate specific antigen velocity from a nadir of 0.4 ng/ml was 0.6 ng/ml. In phase 2, 48 of 179 (26.8%) men underwent repeat biopsy at a mean of 14.6 months. Of these 48 men 26 (54.1%) were found to have prostate cancer. Of the 26 men in whom prostate cancer was detected 20 (76.9%) were found to have Gleason score 7 or greater disease.
Conclusions The magnitude of change in serum prostate specific antigen after 5α-reductase inhibitor therapy may be useful in diagnosing prostate cancer in patients with persistently increased or fluctuating prostate specific antigen and prior negative prostate biopsy.
文献链接： Prostate Biopsy in Response to a Change in Nadir Prostate Specific Antigen of 0.4 ng/ml after Treatment with 5α-Reductase Inhibitors Markedly Enhances the Detection Rate of Prostate Cancer
