Sridhara R, Eisenberger M A, Sinibaldi V J, Reyno L M, Egorin M J
Department of Epidemiology and Preventive Medicine, University of Maryland Cancer Center, Baltimore 21201, USA.
J Clin Oncol. 1995 Dec;13(12):2944-53. doi: 10.1200/JCO.1995.13.12.2944.
We evaluated the surrogate role of serum prostate-specific antigen (PSA) using prospectively collected information from patients with hormone-refractory prostate cancer (HRPC) treated with suramin.
Data from 103 patients were analyzed using survival analysis, exploratory analysis, and regression analysis.
There was a significant survival difference between groups of patients with a PSA decrease of < or = 0% or greater than 0% (P = .018). There were no significant overall survival differences between groups of patients with PSA decreases less than 50% or > or = 50% and less than 75% or > or = 75%. Tree-based modeling did not define a specific threshold percentage PSA change as a response criterion. For a response of 1-year survival, sensitivity increased (0.91 v 0.69), but specificity decreased (0.37 v 0.62), with a 75% versus 50% PSA decrease used as classification criterion. Differences between the area under the receiver-operating curves (ROCs) with 50% and 75% PSA decreases as threshold values were small. For a response of 1-year survival, attributable proportions were 0.38 and 0.68, respectively, with 50% and 75% PSA decreases as threshold values. When pretreatment variables were assessed by Cox proportional hazards model, hemoglobin level was the most significant predictor of survival. When percentage PSA change was included in the model, hemoglobin level remained the most significant factor, but percentage PSA change was also a weak, but statistically significant, factor. PSA was a weak, but statistically significant, predictor of survival in Cox proportional hazards model with PSA as a time-variant covariate.
Reduction in PSA level has weak prognostic significance with respect to survival in HRPC patients, but, currently, PSA reduction cannot be used as a reliable response criterion to evaluate treatment efficacy in individual patients. Prospective, randomized studies, including prospective measurement of other indices related to symptomatic clinical benefits, are required.
我们利用前瞻性收集的接受苏拉明治疗的激素难治性前列腺癌（HRPC）患者的信息，评估血清前列腺特异性抗原（PSA）的替代作用。
对103例患者的数据进行生存分析、探索性分析和回归分析。
PSA下降≤0%或>0%的患者组之间存在显著的生存差异（P = 0.018）。PSA下降<50%或≥50%以及<75%或≥75%的患者组之间总体生存无显著差异。基于树的建模未将特定的PSA变化阈值百分比定义为反应标准。对于1年生存反应，以PSA下降75%与50%作为分类标准时，敏感性增加（0.91对0.69），但特异性降低（0.37对0.62）。以50%和75%的PSA下降作为阈值时，受试者操作特征曲线（ROC）下面积的差异较小。对于1年生存反应，以50%和75%的PSA下降作为阈值时，归因比例分别为0.38和0.68。当通过Cox比例风险模型评估预处理变量时，血红蛋白水平是生存的最显著预测因素。当模型中纳入PSA变化百分比时，血红蛋白水平仍然是最显著的因素，但PSA变化百分比也是一个微弱但具有统计学意义的因素。在以PSA作为时间变化协变量的Cox比例风险模型中，PSA是生存的一个微弱但具有统计学意义的预测因素。
PSA水平降低在HRPC患者生存方面的预后意义较弱，但目前，PSA降低不能用作评估个体患者治疗疗效的可靠反应标准。需要进行前瞻性随机研究，包括前瞻性测量与症状性临床获益相关的其他指标。
