Department of Urology, Stanford University School of Medicine, Stanford, California 94305-5826, USA.
J Urol. 2011 Jun;185(6):2108-11. doi: 10.1016/j.juro.2011.02.053. Epub 2011 Apr 15.
Prior radical prostatectomy series have shown an inverse association between prostate size and high grade cancer. It has been suggested that smaller size prostates arise in a low androgen environment, enabling development of more aggressive cancer. We propose that this observation is the result of ascertainment bias driven by prostate specific antigen performance.
We identified 1,404 patients from the Stanford Radical Prostatectomy Database with clinical stage T1c (723) and T2 (681) disease who underwent surgery between 1988 and 2002, and underwent detailed morphometric mapping by a single pathologist. Multivariate linear regression was performed to assess for the effects of age, prostate weight and prostate specific antigen on total and high grade (Gleason grade 4/5) cancer volume and percentage of high grade disease.
In patients who underwent biopsy due to abnormal prostate specific antigen (stage T1c), prostate weight was negatively associated (p = 0.0002) with total cancer volume, volume of high grade disease and percentage of high grade disease. For patients who underwent biopsy based on abnormal digital rectal examination (stage T2) these associations were not observed.
Improved prostate specific antigen performance for high grade disease results in ascertainment bias in patients with T1c disease. Thus, the association between prostate size and high grade disease may be a consequence of grade dependent performance of prostate specific antigen rather than true tumor biology.
先前的根治性前列腺切除术系列研究表明，前列腺体积与高级别癌症之间存在反比关系。有人认为，较小体积的前列腺是在雄激素水平较低的环境中产生的，从而导致更具侵袭性的癌症发展。我们提出，这种观察结果是由前列腺特异性抗原（PSA）检测性能导致的选择偏差造成的。
我们从斯坦福根治性前列腺切除术数据库中确定了 1404 名临床分期为 T1c（723 例）和 T2（681 例）的患者，这些患者于 1988 年至 2002 年间接受了手术，并由一位病理学家进行了详细的形态计量学图谱分析。采用多元线性回归分析评估年龄、前列腺重量和 PSA 对总癌症体积和高级别（Gleason 分级 4/5）癌症体积及高级别肿瘤比例的影响。
在因 PSA 异常而接受活检的患者（T1c 期）中，前列腺重量与总癌症体积、高级别癌症体积和高级别肿瘤比例呈负相关（p = 0.0002）。对于因直肠指检异常而接受活检的患者（T2 期），这些相关性并未观察到。
PSA 对高级别癌症的检测性能提高会导致 T1c 期患者的选择偏差。因此，前列腺体积与高级别癌症之间的关联可能是 PSA 与肿瘤分级相关的检测性能的结果，而不是真正的肿瘤生物学原因。
