THE DELAY BEFORE ONSET OF ACCELERATED TUMOR-CELL REPOPULATION DURING RADIOTHERAPY - A DIRECT MAXIMUM-LIKELIHOOD ANALYSIS OF A COLLECTION OF WORLDWIDE TUMOR-CONTROL DATA
THE DELAY BEFORE ONSET OF ACCELERATED TUMOR-CELL REPOPULATION DURING RADIOTHERAPY - A DIRECT MAXIMUM-LIKELIHOOD ANALYSIS OF A COLLECTION OF WORLDWIDE TUMOR-CONTROL DATA
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DOI：
10.1016/0167-8140(93)90175-8
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发表时间：
1993-10-01
影响因子：
5.7
通讯作者：
HENDRY, JH
中科院分区：
文献类型：
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作者：
ROBERTS, SA;HENDRY, JH
由Withers等人（Withers，H.R.，泰勒，J.M.G.和Maciebenski，B.肿瘤学学报27：131-146，1988）使用包括肿瘤克隆原再增殖开始之前的明确滞后期的模型进行重新分析。一个直接的最大似然法被用来和方法扩展到包括计算配置文件似然置信限。获得了29天的统计学显著性（p = 0.02）滞后，95%置信限涵盖17-31天范围。然而，置信区间被断开，并排除了21-23天的时间段。分析得出的时间因子为0.66戈伊/天。平均值证实了原作者使用两阶段（间接）方法得出的结论，并且该值与此处针对另一个包含496例患者的数据集（滞后期= 26（19-33）天）计算的值相似。然而，数据集本身是回顾性的，并可能受到一些偏见。因此，任何临床结论都只能是初步的。该方法的一个新特点是计算配置文件的似然置信限，这将是有用的，在未来的直接分析这种类型的临床数据。通常计算的正态近似的置信限已被证明是不够的，在这种分析中，无论是配置文件的似然限或似然比测试必须采用，以确定模型参数的意义。
The worldwide collection of control data for head and neck tumours presented by Withers et al. (Withers, H.R., Taylor, J.M.G. and Maciejewski, B. Acta Oncol. 27: 131-146, 1988) was reanalysed using a model which includes an explicit lag phase before the onset of tumour clonogen repopulation. A direct maximum-likelihood approach was used and the methodology extended to include the computation of profile-likelihood confidence limits. A statistically significant (p = 0.02) lag of 29 days was obtained with 95% confidence limits covering the range 17-31 days. However, the confidence interval was disconnected, and excluded the period 21-23 days. The analysis gave a time factor of 0.66 Gy/day. The mean values confirm the conclusions drawn by the original authors using a two-stage (indirect) method, and the values are similar to those calculated here for another data set comprising 496 patients (lag period = 26 (19-33) days). However, the data set itself is retrospective, and potentially subject to a number of biases. Therefore any clinical conclusions can only be tentative. A new feature of the methodology is the computation of profile-likelihood confidence limits and this will be useful in future direct analyses of clinical data of this type. The more usually computed normal approximation to the confidence limits have been shown to be inadequate in this analysis, and either profile-likelihood limits or likelihood ratio tests must be employed to determine the significance of the model parameters.