Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania.
Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York.
Int J Radiat Oncol Biol Phys. 2020 May 1;107(1):79-87. doi: 10.1016/j.ijrobp.2020.01.014. Epub 2020 Jan 25.
We hypothesized that the radiation dose in high-ventilation portions of the lung better predicts radiation pneumonitis (RP) outcome for patients treated with proton radiation therapy (PR) and photon radiation therapy (PH).
Seventy-four patients (38 protons, 36 photons) with locally advanced non-small cell lung cancer treated with concurrent chemoradiation therapy were identified, of whom 24 exhibited RP (graded using Common Terminology Criteria for Adverse Events v4.0) after PR or PH, and 50 were negative controls. The inhale and exhale simulation computed tomography scans were deformed using Advanced Normalization Tools. The 3-dimensional lung ventilation maps were derived from the deformation matrix and partitioned into low- and high-ventilation zones for dosimetric analysis. Receiver operating curve analysis was used to study the power of relationship between RP and ventilation zones to determine an optimal ventilation cutoff. Univariate logistic regression was used to correlate dose in high- and low-ventilation zones with risk of RP. A nonparametric random forest process was used for multivariate importance assessment.
The optimal high-ventilation zone definition was determined to be the higher 45% to 60% of the ventilation values. The parameter vV20Gy_high (high ventilation volume receiving ≥20 Gy) was found to be a significant indicator for RP (PH: P = .002, PR: P = .035) with improved areas under the curve compared with the traditional V20Gy for both photon and proton cohorts. The relationship of RP with dose to the low-ventilation zone of the lung was insignificant (PH: P = .123, PR: P = .661). Similar trends were observed for ventilation mean lung dose and ventilation V5Gy. Multivariate importance assessment determined that vV20Gy_high, vV5_high, and mean lung dose were the most significant parameters for the proton cohort with a combined area under the curve of 0.78.
Dose to the high-ventilated regions of the lung can improve predictions of RP for both PH and PR.
我们假设，在接受质子放射治疗（PR）和光子放射治疗（PH）的患者中，肺部高通气部分的辐射剂量能更好地预测放射性肺炎（RP）的结果。
共确定了 74 例局部晚期非小细胞肺癌患者（38 例质子，36 例光子），这些患者接受了同期放化疗，其中 24 例在接受 PR 或 PH 后出现 RP（采用通用不良事件术语标准 4.0 进行分级），50 例为阴性对照。吸气和呼气模拟 CT 扫描使用高级归一化工具进行变形。从变形矩阵中推导出 3 维肺通气图，并将其分为低通气区和高通气区进行剂量分析。接收器操作曲线分析用于研究 RP 与通气区之间关系的相关性，以确定最佳通气截止值。单变量逻辑回归用于分析高、低通气区剂量与 RP 风险的相关性。非参数随机森林过程用于多变量重要性评估。
确定高通气区的最佳定义为通气值的较高 45%至 60%。参数 vV20Gy_high（高通气量接收≥20 Gy）被发现是 RP 的一个重要指标（PH：P =.002，PR：P =.035），与光子和质子队列的传统 V20Gy 相比，曲线下面积有所提高。RP 与肺低通气区剂量的关系不显著（PH：P =.123，PR：P =.661）。对于通气平均肺剂量和通气 V5Gy，也观察到了类似的趋势。多变量重要性评估确定，vV20Gy_high、vV5_high 和平均肺剂量是质子队列最重要的参数，综合曲线下面积为 0.78。
肺部高通气区的剂量可以提高 PH 和 PR 患者的 RP 预测准确性。
