Is α/β for prostate tumors really low?
Is α/β for prostate tumors really low?
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DOI：
10.1016/s0360-3016(01)01607-8
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发表时间：
2001-07-15
影响因子：
7
通讯作者：
Ritter, M
中科院分区：
文献类型：
--
作者：
Fowler, J;Chappell, R;Ritter, M
目的：Brenner 和 Hall 1999 年的论文估计前列腺肿瘤的 α/β 值为 1.5 Gy，这引起了人们对前列腺肿瘤中这个比率（固有放射敏感性与修复能力）是否比其他增殖更快的类型肿瘤低得多的问题的兴趣。使用更少和更大的分数可能治疗前列腺癌的意义很重要。在本文中，我们回顾了更新的临床数据，并提出了一些不同的计算来估计 α/β。 方法和材料：回顾了 1995 年至 2000 年发表的 17 篇临床论文，以获得仅使用外照射、I-125 植入物或 Pd-103 植入物进行放射治疗的生化控制的估计，重点是中等风险患者。采用了三种估计α/β的方法。首先，对来自外束和植入方式的等有效剂量进行了简单的两步图形比较，以了解哪个 α/β 值可以预测观察到的生物效应特性。其次，对相同的数据进行直接分析（最大似然估计），从中获得α/β的估计以及肿瘤亚致死损伤修复的T1/2（均具有置信区间）。第三，分析了比较两种不同大小的高剂量加强剂量的初步临床数据，其中在2年时观察到显着不同的bNED。结果：第二种方法给出了最终结果：α/β = 1.49 Gy（95% CI 1.25-1.76）和T1/2 = 1.90 h（95% CI 1.42-2.86 h）。第一种方法给出了 1.4 至 1.9 Gy 的范围，并表明如果使用平均或中位剂量而不是规定剂量，α/β 的估计值将大大低于 1 Gy。第三种方法虽然基于早期随访，但与 2 Gy 或以下区域的 α/β 低值一致。 T1/2 的估计值是前列腺肿瘤原位报告的第一个值。结论：所有估计值都指向较低的 α/β 值，至少与 Brenner 和 Hall 的估计值一样低，并且可能低于晚期并发症约 3 Gy 的预期值。似乎需要针对中危前列腺癌进行大分割试验。 (C) 2001 爱思唯尔科学公司。
Purpose: Brenner and Hall's 1999 paper estimating an alpha/beta value of 1.5 Gy for prostate tumors has stimulated much interest in the question of whether this ratio (of intrinsic radiosensitivity to repair capacity) is much lower in prostate tumors than in other types of tumors that proliferate Faster. The implications for possibly treating prostatic cancer using fewer and larger fractions are important. In this paper we review updated clinical data and present somewhat different calculations to estimate alpha/beta.Methods and Materials: Seventeen clinical papers published from 1995 to 2000 were reviewed to obtain estimates of biochemical control from radiotherapy alone using external beam, I-125 implants, or Pd-103 implants, The focus was on intermediate risk patients. Three methods of estimating alpha/beta were employed. First, a simple two-step graphical comparison of isoeffective doses from external beam and implant modalities was made, to see which value of alpha/beta predicted the observed identity of biologic effect. Second, the same data were subjected to Direct Analysis (maximum likelihood estimation), from which an estimate of alpha/beta and also of the T1/2 of repair of sublethal damage in the tumors (both with confidence intervals) were obtained. Third, preliminary clinical data comparing two different sizes of high-dose boost doses were analyzed in which significantly different bNED was observed at 2 years.Results: The second method gave the definitive result of alpha/beta = 1.49 Gy (95% CI 1.25-1.76) and T1/2 = 1.90 h (95% CI 1.42-2.86 h). The first method gave a range from 1.4 to 1.9 Gy and showed that if mean or median dose were used instead of prescribed dose, the estimate of alpha/beta would be substantially below 1 Gy. The third method, although based on early follow-up, was consistent with low values of alpha/beta in the region of 2 Gy or below. The estimate for T1/2 is the first value reported for prostate tumors in situ.Conclusions: All the estimates point toward low values of alpha/beta, at least as low as the estimates of Brenner and Hall, and possibly lower than the expected values of about 3 Gy for late complications. Hypofractionation trials for intermediate-risk prostatic cancer appear to be indicated. (C) 2001 Elsevier Science Inc.