Department of Urology, Vall d'Hebron Hospital, Autonoma University of Barcelona, Spain.
BJU Int. 2010 Feb;105(4):481-4. doi: 10.1111/j.1464-410X.2009.08761.x. Epub 2009 Aug 13.
To analyse the ratio of serum testosterone (sT) to prostate-specific antigen (PSA) as a predictor of prostate cancer risk, as low levels of sT have been related to a greater risk of prostate cancer, and its ratio with serum PSA level was recently proposed as a new tool to increase the specificity of PSA.
In all, 439 consecutive men with a normal digital rectal examination and a serum PSA level of 4.1-20 ng/mL had a transrectal ultrasonography-guided biopsy using a 10-core scheme, with an additional 1-8 cores according to prostate volume and patient age. The sT level was determined before the procedure using a chemiluminescent assay, and the ratio of sT to PSA (sT/PSA) was calculated after transforming sT measurements from ng/dL to ng/mL. The percentage free PSA (%fPSA) and PSA density were also included in this analysis.
The overall cancer detection rate was 42.1%. The median sT level was 469 ng/dL in men with cancer and 499 ng/dL in those without (P = 0.521). The median sT/PSA was 0.68 and 0.74, respectively (P = 0.215). However, the median %fPSA was 14 in men with cancer and 17 in men without (P < 0.001) and the median PSA density was 0.22 and 0.16, respectively (P < 0.001). The multivariate analysis confirmed the independent predictive value only for %fPSA (odds ratio 0.94, 95% confidence interval 0.91-0.98) and PSA density (5.8, 3.42-19.8).
These results do not support the use of sT/PSA for predicting the risk of prostate cancer and to increase the specificity of PSA.
分析血清睾酮（sT）与前列腺特异性抗原（PSA）的比值作为前列腺癌风险的预测指标，因为低水平的 sT 与前列腺癌风险增加有关，并且其与血清 PSA 水平的比值最近被提出作为一种新的工具来提高 PSA 的特异性。
总共对 439 名接受直肠指检和血清 PSA 水平为 4.1-20ng/mL 的连续男性进行了经直肠超声引导下的活检，采用 10 核方案，根据前列腺体积和患者年龄增加 1-8 核。sT 水平在进行该程序前使用化学发光测定法确定，并且 sT/PSA（sT/PSA）的比值在将 sT 测量值从 ng/dL 转换为 ng/mL 后计算。在该分析中还包括游离 PSA（%fPSA）和 PSA 密度。
总体癌症检出率为 42.1%。癌症患者的中位 sT 水平为 469ng/dL，非癌症患者为 499ng/dL（P=0.521）。中位 sT/PSA 分别为 0.68 和 0.74（P=0.215）。然而，癌症患者的中位 %fPSA 为 14，非癌症患者为 17（P<0.001），并且中位 PSA 密度分别为 0.22 和 0.16（P<0.001）。多变量分析仅证实了 %fPSA（比值比 0.94，95%置信区间 0.91-0.98）和 PSA 密度（5.8，3.42-19.8）的独立预测价值。
这些结果不支持使用 sT/PSA 来预测前列腺癌的风险和提高 PSA 的特异性。
