Dose-volume modeling of salivary function in patients with head-and-neck cancer receiving radiotherapy
Dose-volume modeling of salivary function in patients with head-and-neck cancer receiving radiotherapy
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DOI：
10.1016/j.ijrobp.2004.12.076
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发表时间：
2005-07-15
影响因子：
7
通讯作者：
Deasy, JO
中科院分区：
文献类型：
--
作者：
Blanco, AI;Chao, KSC;Deasy, JO
目的：我们调查了影响唾液功能的因素，头颈部放疗（RT）后，包括腮腺剂量体积效应，潜在的补偿少照射的腺体组织，随着时间的推移和功能恢复。方法和材料：65例头颈部肿瘤患者参加了前瞻性唾液功能研究。使用调强RT（n = 45）、前瞻性计划三维适形RT（it = 14）或三维适形RT+调强RT增强（it = 6）进行RT。在治疗前和RT后6个月（n = 61）和12个月（n = 31）测量全唾液流量。测试了各种剂量-体积模型来预测RT后唾液功能。根据主观、客观、管理、分析（索马）标准，口干症定义为治疗后唾液功能<治疗前功能的25%。多变量逻辑回归分析被用来评估剂量体积，病人，和治疗相关factors.Results：一个显着的相关性之间的相对生活质量评分和相对刺激唾液值RT后6个月观察（斯皮尔曼的相关系数[R-s] = 0.46，p < 0.001）。剂量-体积因素与刺激唾液流量的相关性最强，尽管其他因素在多指标模型（化疗、性别和Karnofsky体能状态）中显示出适度的显著性。几个拟合的剂量-体积模型提供了数据的良好数学描述。唾液测量中的显著噪声（正常受试者的重复测量变异系数为27%）排除了仅根据客观拟合标准选择任何一种模型。然而，平均剂量指数模型，其中每个腮腺的相对唾液腺功能等于exp（-A x平均腺体剂量），A等于0.054/戈伊（68%置信区间0.052-0.059），提供了一个很好的数据表示，并纳入我们的多指标分析。使用该模型，我们估计，平均腮腺剂量为25.8戈伊，平均，可能会减少一个单一的腮腺的流量，其治疗前的值的25%，无论治疗输送方法。Logistic多变量模型之间存在显著相关性，（结合平均剂量指数方程、性别和Karnofsky体力状态）和6个月时的刺激唾液流量（R-s = 0.73），12个月时的刺激唾液流量（R-s = 0.54）和6个月时的生活质量评分（R-s = 0.35）。结论：刺激腮腺唾液腺剂量-体积模型与刺激唾液功能和唾液质量密切相关RT后6个月的生活评分。RT后6个月至12个月，平均刺激唾液流速有所改善。每个腺体的唾液功能似乎以平均剂量约5%/1戈伊的速率呈指数级丧失。有必要进行更多的研究，以区分治疗计划中使用的模型。当至少一个腮腺的平均剂量保持在常规分割的< 25.8戈伊时，口干症的发生率显著降低。然而，甚至更低的平均剂量意味着晚期唾液功能增加。(c)2005年爱思唯尔公司
Purpose: We investigated the factors that affect salivary function after head-and-neck radiotherapy (RT), including parotid gland dose-volume effects, potential compensation by less-irradiated gland tissue, and functional recovery over time.Methods and Materials: Sixty-five patients with head-and-neck tumors were enrolled in a prospective salivary function study. RT was delivered using intensity-modulated RT (n = 45), forward-planning three-dimensional conformal RT (it = 14), or three-dimensional conformal RT with an intensity-modulated RT boost (it = 6). Whole salivary flow was measured before therapy and at 6 months (n = 61) and 12 months (n = 31) after RT. A wide variety of dose-volume models to predict post-RT salivary function were tested. Xerostomia was defined according to the subjective, objective, management, analytic (SOMA) criteria as occurring when posttreatment salivary function was < 25% of the pretreatment function. Multivariate logistic regression analysis was used to assess the combined effect of dose-volume, patient-, and treatment-related factors.Results: A significant correlation was observed between the relative quality-of-life scores and relative stimulated saliva values at 6 months after RT (Spearman's correlation coefficient [R-s] = 0.46, p < 0.001). The dose-volume factors were by far the strongest correlates with stimulated saliva flow, although other factors showed modest significance in multimetric models (chemotherapy, gender, and Karnofsky performance status). Several fitted dose-volume models provided a good mathematical description of the data. Significant noise in the salivary measurements (repeated measurement coefficient of variation was 27% in normal subjects) precluded selection of any one of the models presented solely on the basis of the objective fit criteria. Nevertheless, the mean dose-exponential model, in which each parotid gland's relative salivary gland function equaled exp(-A x mean gland dose), with A equal to 0.054/Gy (68% confidence interval 0.052-0.059), provided a good representation of the data and was incorporated into our multimetric analysis. Using that model, we estimated that a mean parotid dose of 25.8 Gy, on average, was likely to reduce a single parotid gland's flow to 25% of its pretreatment value, regardless of the treatment delivery method. Significant correlations were observed between a logistic multivariate model (incorporating the mean dose-exponential equation, gender, and Karnofsky performance status) and stimulated saliva flow at 6 months (R-s = 0.73), stimulated saliva flow at 12 months (R-s = 0.54), and quality-of-life score at 6 months (R-s = 0.35) after RT.Conclusion: Stimulated parotid salivary gland dose-volume models strongly correlated with both stimulated salivary function and quality-of-life scores at 6 months after RT. The mean stimulated saliva flow rates improved from 6 to 12 months after RT. Salivary function, in each gland, appeared to be lost exponentially at a rate of approximately 5%/1 Gy of mean dose. Additional research is necessary to distinguish among the models for use in treatment planning. The incidence of xerostomia was significantly decreased when the mean dose of at least one parotid gland was kept to < 25.8 Gy with conventional fractionation. However, even lower mean doses imply increased late salivary function. (c) 2005 Elsevier Inc.