Morote Juan, Planas Jacques, Salvador Carlos, Raventós Carles X, Catalán Roberto, Reventós Jaume
Department of Urology, Vall d'Hebron Hospital, Autónoma University of Barcelona, Barcelona, Spain.
BJU Int. 2009 Feb;103(3):332-5; discussion 335. doi: 10.1111/j.1464-410X.2008.08062.x. Epub 2008 Oct 31.
To analyse individual variations in serum testosterone level, the cumulative rate of 'breakthrough' increases over castrate levels, and to evaluate whether the increases can be predicted.
Serum testosterone levels were determined every 6 months over 3 years in 73 consecutive patients with prostate cancer who were medically castrated, prospectively enrolled in a single tertiary academic centre. Patients recruited for this study were being treated with a 3-monthly depot of luteinizing hormone-releasing hormone agonist over 6-48 months. Serum testosterone was measured using a chemiluminescent assay with a lower sensitivity level of 15 ng/dL and interassay coefficient of variation of 25% at low testosterone concentrations.
Individual variations could not be explained by the interassay variation coefficient in 26% of the patients. The rate of breakthrough increases >50 ng/dL increased from 12.3% at the first determination to 24.7% at the third, then remaining stable. The rate of breakthrough increases of 20-50 ng/dL increased from 27.4% at the first determination to 31.5% at the second, and then remained stable. A first determination of <20 ng/dL provided an 11.4% probability for future increases of >50 ng/dL, with a 5.7% probability if two consecutive determinations were <20 ng/dL and a null probability when three consecutive determinations were <20 ng/dL.
Individual variations in serum testosterone level cannot be explained by the coefficient of variation of the assay in a quarter of patients who are medically castrated. Breakthrough increases over castrate levels increase over time and those of >50 ng/dL can be predicted from the previous levels.
分析血清睾酮水平的个体差异、超过去势水平的“突破”累积发生率，并评估这些增加是否可以预测。
在一个单一的三级学术中心前瞻性招募了73例接受药物去势的前列腺癌患者，在3年时间里每6个月测定一次血清睾酮水平。本研究招募的患者接受了6至48个月的每3个月一次的促黄体生成素释放激素激动剂长效注射治疗。采用化学发光法测定血清睾酮，低睾酮浓度时的最低检测限为15 ng/dL，批间变异系数为25%。
26%的患者个体差异无法用批间变异系数来解释。突破增加>50 ng/dL的发生率从首次测定时的12.3%增加到第三次测定时的24.7%，然后保持稳定。突破增加20至50 ng/dL的发生率从首次测定时的27.4%增加到第二次测定时的31.5%，然后保持稳定。首次测定<20 ng/dL时，未来增加>50 ng/dL的概率为11.4%，如果连续两次测定<20 ng/dL，概率为5.7%，如果连续三次测定<20 ng/dL，则概率为零。
在四分之一接受药物去势的患者中，血清睾酮水平的个体差异无法用检测的变异系数来解释。超过去势水平的突破增加随时间推移而增加，且>50 ng/dL的增加可以根据先前水平预测。
