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Abstract：
No clear criteria have yet been established to guide decision-making for patient selection and the optimal timing of adaptive radiotherapy (ART) based on image-guided radiotherapy (IGRT). We have developed a novel protocol—the Best for Adaptive Radiotherapy (B-ART) protocol—to guide patient selection for ART. The aim of the present study is to describe this protocol, to evaluate its validity in patients with head and neck (HN) cancer, and to identify the anatomical and clinical predictors of the need for replanning. We retrospectively evaluated 82 patients with HN cancer who underwent helical tomotherapy (HT) and subsequently required replanning due to soft tissue changes upon daily MVCT. Under the proposed criteria, patients with anatomical changes >3 mm on three to four consecutive scans are candidates for ART. We compared the volumes on the initial CT scan (iCT) and the replanning CT (rCT) scan for the clinical target volumes (CTV1, referring to primary tumor or tumor bed and CTV2, metastatic lymph nodes) and for the parotid glands (PG) and body contour (B-body). The patients were stratified by primary tumor localization, clinical stage, and treatment scheme. The main reasons for replanning were: (1) a planning target volume (PTV) outside the body contour (n = 70; 85.4%), (2) PG shrinkage (n = 69; 84.1%), (3) B-body deviations (n = 69; 84.1%), and (4) setup deviations (n = 40; 48.8%). The replanning decision was made, on average, during the fourth week of treatment (n = 47; 57.3%). The mean reductions in the size of the right and left PG volumes were 6.31 cc (20.9%) and 5.98 cc (20.5%), respectively (p < 0.001). The reduction in PG volume was ≥30% in 30 patients (36.6%). The volume reduction in all of the anatomical structures was statistically significant. Four variables—advanced stage disease (T3−T4), chemoradiation, increased weight loss, and oropharyngeal localization—were significantly associated with the need for ART. The B-ART protocol provides clear criteria to eliminate random errors, and to allow for an early response to relevant changes in target volumes.
摘要：
尚未建立明确的标准来指导患者选择的决策以及基于图像引导放射治疗（IGRT）的自适应放射治疗（ART）的最佳时机。我们开发了一种新的协议-最佳自适应放射治疗（B-ART）协议-以指导患者选择ART。本研究的目的是描述这个协议，评估其在头颈部（HN）癌症患者中的有效性，并确定需要重新规划的解剖学和临床预测因素。我们回顾性评估了82例HN癌症患者，这些患者接受了螺旋断层治疗（HT），随后由于每天的MVCT软组织变化而需要重新计划。根据拟议的标准，在3~4次连续扫描中解剖改变>3mm的患者是ART的候选对象.我们比较了初始CT扫描（iCT）和重新计划CT（rCT）扫描的临床目标体积（CTV1，指原发性肿瘤或瘤床，CTV2，转移性淋巴结）和腮腺的体积（PG）和身体轮廓（B体）。患者按原发肿瘤定位进行分层,临床分期,和治疗方案。重新计划的主要原因是：（1）身体轮廓外的计划目标体积（PTV）（n=70；85.4％），(2)PG收缩率(n=69；84.1%)，(3)B体偏差(n=69；84.1%)，(4)设置偏差(n=40；48.8%)。做出了重新规划的决定，平均而言,在治疗的第四周（n=47;57.3％）。右侧和左侧PG体积的平均减少量为6.31cc（20.9％）和5.98cc（20.5％），分别(p<0.001)。30例患者的PG体积减少≥30％（36.6％）。所有解剖结构的体积减少具有统计学意义。四个变量-晚期疾病（T3-T4），放化疗,增加体重减轻，和口咽定位-与ART的需要显著相关。B-ART协议提供了明确的标准来消除随机错误，并允许对目标卷的相关变化做出早期响应。
