Department of Urology, Azienda Ospedaliera, Universitaria di Verona, Ospedale Civile Maggiore, Verona, Italy.
Int Urol Nephrol. 2010 Sep;42(3):673-81. doi: 10.1007/s11255-009-9669-z. Epub 2009 Nov 10.
To show that prostate cancer biology is related to serum levels of both free testosterone (FT) and prostate-specific antigen (PSA), that PSA level is linearly related to FT and that the PSA to FT ratio may be considered as the growth rate parameter expressing cancer phenotype biology.
The study includes 135 consecutive patients diagnosed with prostate cancer. Pretreatment simultaneous serum samples for analyzing total testosterone (TT), FT and total PSA levels were obtained. The study was assessed according to a multidimensional approach of the five continuous variables including TT, FT, PSA, AGE and percentage of positive biopsies (=P+). The all sets of data were considered as one--sample with no groupings among the observations. Multivariate analysis included factor analysis (FA) and principal component analysis (PCA). Multivariate inferential statistics for comparing different groups of patients according to the PSA to free testosterone ratio (PSA/FT) included Hotteling's multivariate two-sample T²-Test for comparing two mean vectors as well as Box's M-Test with the chi-square approximation for comparing multiple covariance matrices when patients were sampled in more than two groups.
Factor analysis showed the two natural grouping of variables, FT-TT and PSA-P+. PCA assessed FT and PSA as the two variables with large variances having a notable influence on the first two principal components. Multiple linear regression analysis showed that all the income variables, except age, significantly predicted the PSA/FT ratio. Patients were first sampled according to the PSA/FT ratio in group 1 (PSA/FT ≤ 0.20) and group 2 (PSA/FT > 0.20), and Hotteling's multivariate two sample T²-Test was significant (P < 0.01). Patients were then sampled according to the PSA/FT ratio in group 1 (PSA/FT ≤ 0.20), group 2 (PSA/FT > 0.20 and ≤ 0.40), and group 3 (PSA/FT > 0.40), and Box's M-Test comparing the covariance matrices of the 3 groups differed significantly (P < 0.001). Finally, patients were sampled according to the PSA/FT ratio in 6 groups, and Box's M-Test was again significant (P < 0.001).
The PSA to FT ratio is the growing rate parameter expressing different biology patterns and assessing different groups of prostate cancer patients. In our opinion, the results of the present study might have wide applications in understanding, assessing and planning prostate cancer studies including basic science, screening, assessing risk of the disease, predicting disease stage as well natural history after a planned treatment involving biochemical recurrence, progression, hormone refractory prostate cancer and disease-specific survival.
表明前列腺癌生物学与游离睾酮（FT）和前列腺特异性抗原（PSA）的血清水平有关，PSA 水平与 FT 呈线性相关，PSA 与 FT 的比值可被视为表达癌症表型生物学的生长率参数。
本研究纳入了 135 例连续诊断为前列腺癌的患者。获得了治疗前同时分析总睾酮（TT）、FT 和总 PSA 水平的血清样本。该研究根据包括 TT、FT、PSA、年龄和阳性活检百分比（=P+）在内的五个连续变量的多维方法进行评估。所有数据集均被视为一个样本，观察结果之间没有分组。多变量分析包括因子分析（FA）和主成分分析（PCA）。根据 PSA 与游离睾酮比值（PSA/FT）比较不同患者组的多变量推断统计包括比较两个均值向量的 Hotteling 多变量两样本 T²检验，以及当患者分组超过两组时使用卡方逼近比较多个协方差矩阵的 Box M 检验。
因子分析显示了变量 FT-TT 和 PSA-P+的两个自然分组。PCA 将 FT 和 PSA 评估为具有显著影响前两个主成分的两个方差较大的变量。多元线性回归分析表明，除年龄外，所有收入变量均显著预测 PSA/FT 比值。患者首先根据 PSA/FT 比值分为第 1 组（PSA/FT≤0.20）和第 2 组（PSA/FT>0.20），Hotteling 多变量两样本 T²检验有显著差异（P<0.01）。然后根据 PSA/FT 比值将患者分为第 1 组（PSA/FT≤0.20）、第 2 组（PSA/FT>0.20 和≤0.40）和第 3 组（PSA/FT>0.40），Box M 检验比较三组协方差矩阵有显著差异（P<0.001）。最后，根据 PSA/FT 比值将患者分为 6 组，Box M 检验再次有显著差异（P<0.001）。
PSA 与 FT 的比值是表达不同生物学模式和评估不同前列腺癌患者组的生长率参数。我们认为，本研究的结果可能在理解、评估和规划包括基础科学、筛查、评估疾病风险、预测疾病阶段以及计划治疗后的生化复发、进展、激素难治性前列腺癌和疾病特异性生存等方面具有广泛的应用。
