Kulkarni Girish S, Al-Azab Rami, Lockwood Gina, Toi Ants, Evans Andrew, Trachtenberg John, Jewett Michael A S, Finelli Antonio, Fleshner Neil E
Division of Urology, Princess Margaret Hospital, University of Toronto, Toronto, Canada.
J Urol. 2006 Feb;175(2):505-9. doi: 10.1016/S0022-5347(05)00236-3.
The PCPT has demonstrated a higher incidence of high grade (Gleason pattern 4 or greater) prostate cancers among men randomized to finasteride. One plausible explanation for this finding is that tumor grade as assigned by TRUS guided biopsy is artifactually associated with prostate volume.
We evaluated our institutional data set of TRUS guided biopsies in the last 3 years and identified 369 cases of prostate cancer that fit the criteria of PSA less than 10 ng/ml, biopsy at our center and RP at our center. We identified risk factors for Gleason pattern 4 or greater on biopsy and then on RP specimens from the same patients using univariate and multiple logistic regression analyses. Assessed covariates included patient age, PSA and TRUS volume.
Risk factors for Gleason pattern 4 or greater in the biopsy specimens included age (p = 0.01), hypoechoic lesions on TRUS (p <0.001) and TRUS volume (p = 0.008). However, among RP specimens TRUS volume (p = 0.60) became nonsignificant of Gleason pattern 4 or greater on multivariable analysis. Although prostate volume was a predictor for biopsy derived high grade disease it was not predictive of true histological grade.
These data suggest that simply having a larger prostate results in fewer high grade cancers diagnosed at biopsy. Prostatectomy results in the same men suggest sampling artifact, as the distribution of cancer grade is not associated with prostate volume. These findings provide evidence that the increase in higher grade tumors among men in the finasteride arm of PCPT may simply result from prostate volume reduction.
前列腺癌预防试验（PCPT）表明，随机接受非那雄胺治疗的男性中，高级别（Gleason评分4级或更高）前列腺癌的发病率更高。对此发现的一种合理的解释是，经直肠超声（TRUS）引导下活检所确定的肿瘤分级与前列腺体积存在人为关联。
我们评估了过去3年中经TRUS引导下活检的机构数据集，确定了369例符合前列腺特异性抗原（PSA）低于10 ng/ml、在我们中心进行活检以及在我们中心进行根治性前列腺切除术（RP）标准的前列腺癌病例。我们使用单因素和多因素逻辑回归分析确定活检时以及同一患者RP标本中Gleason评分4级或更高的危险因素。评估的协变量包括患者年龄、PSA和TRUS测量的前列腺体积。
活检标本中Gleason评分4级或更高的危险因素包括年龄（p = 0.01）、TRUS上的低回声病变（p <0.001）和TRUS测量的前列腺体积（p = 0.008）。然而，在RP标本中，多因素分析显示TRUS测量的前列腺体积（p = 0.60）对于Gleason评分4级或更高不再具有统计学意义。尽管前列腺体积是活检得出的高级别疾病的一个预测因素，但它并不能预测真正的组织学分级。
这些数据表明，单纯前列腺体积较大导致活检时诊断出的高级别癌症较少。对同一批男性进行前列腺切除术后的结果提示存在取样假象，因为癌症分级的分布与前列腺体积无关。这些发现提供了证据，表明PCPT中非那雄胺组男性中高级别肿瘤的增加可能仅仅是由于前列腺体积缩小所致。
