Bladder spatial-dose descriptors correlate with acute urinary toxicity after radiation therapy for prostate cancer
Bladder spatial-dose descriptors correlate with acute urinary toxicity after radiation therapy for prostate cancer
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DOI：
10.1016/j.ejmp.2016.08.013
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发表时间：
2016-12-01
影响因子：
3.4
通讯作者：
Fiorino, C.
中科院分区：
文献类型：
--
作者：
Improta, I.;Palorini, F.;Fiorino, C.
目的：评估膀胱空间剂量参数预测前列腺癌（PCa）放射治疗后的急性泌尿毒性，通过逐像素方法分析膀胱剂量表面图（DSM）。材料与方法：一项多机构研究的最后队列，包括539例常规治疗的PCa患者。（CONV：1.8-2戈伊/fr）或中度低分割放疗（HYPO：2.2-2.7戈伊/fr）。在放疗前后通过国际前列腺症状评分（IPSS）评价尿毒性。选择放射治疗结束时IPSS增加>= 10和15分（Delta IPSS >= 10和Delta IPSS >= 15）作为终点。通过逐像素方法比较有/无毒性患者的平均DSM（校正为2 Gy当量剂量）。这允许提取选定的空间描述符来区分有/无毒性的患者。以前的logistic模型的基础上剂量表面直方图（DSH）被认为是取代DSM描述符。辨别力，校准和对数似然被认为是评估的影响，包括空间descriptors.Results：375/539例患者的数据。在76/375（20%）例患者中记录了Delta IPSS >= 10，而30/375（8%）例患者发生了Delta IPSS >= 15。距离膀胱底部12 mm处的后部剂量（大致对应于三角区）与整个/HYPO人群的毒性显著相关。沿着膀胱中心轴的75戈伊等剂量的颅侧延伸是CONV患者中最好的基于DSM的预测因子。与基于DSH的模型（AUC = 0.58-0.71）相比，包括DSM描述符的多变量模型显示出更好的区分度（AUC = 0.66-0.77）和更高的对数似然性。空间描述符的结合提高了歧视和对数似然多变量模型，包括剂量和临床参数。(C)2016年意大利医学协会。由爱思唯尔有限公司出版。保留所有权利。
Purpose: To assess bladder spatial-dose parameters predicting acute urinary toxicity after radiotherapy for prostate cancer (PCa) through a pixel-wise method for analysis of bladder dose-surface maps (DSMs).Materials & methods: The final cohort of a multi-institutional study, consisting of 539 patients with PCa treated with conventionally (CONV: 1.8-2 Gy/fr) or moderately hypo-fractionated radiotherapy (HYPO: 2.2-2.7 Gy/fr) was considered. Urinary toxicity was evaluated through the International Prostate Symptoms Score (IPSS) administered before and after radiotherapy. IPSS increases >= 10 and 15 points at the end of radiotherapy (Delta IPSS >= 10 and Delta IPSS >= 15) were chosen as endpoints. Average DSMs (corrected into 2 Gy-equivalent doses) of patients with/without toxicity were compared through a pixel-wise method. This allowed the extraction of selected spatial descriptors discriminating between patients with/without toxicity. Previously logistic models based on dose-surface histograms (DSH) were considered and replaced with DSM descriptors. Discrimination power, calibration and log-likelihood were considered to evaluate the impact of the inclusion of spatial descriptors.Results: Data of 375/539 patients were available. Delta IPSS >= 10 was recorded in 76/375 (20%) patients, while 30/375 (8%) experienced Delta IPSS >= 15. The posterior dose at 12 mm from the bladder base (roughly corresponding to the trigone region) resulted significantly associated to toxicity in the whole/HYPO populations. The cranial extension of the 75 Gy isodose along the bladder central axis was the best DSM-based predictor in CONV patients. Multi-variable models including DSM descriptors showed better discrimination (AUC = 0.66-0.77) when compared to DSH-based models (AUC = 0.58-0.71) and higher log-likelihoods.Conclusion: DSMs are correlated with the risk of acute GU toxicity. The incorporation of spatial descriptors improves discrimination and log-likelihood of multi-variable models including dosimetric and clinical parameters. (C) 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.