目的:研究中国癌症中心胸段食管癌(TEC)确定性放疗靶区划分的观察者间变异性(IOV)。并最终尽可能提高轮廓的一致性,为多中心前瞻性研究奠定基础。
方法:中国16个癌症中心参与了这项研究。在第1阶段,有上三个合适的情况,中间,选择了较低的TEC,参与者被要求绘制一组大体肿瘤体积(GTV-T)的轮廓,根据常规经验,每个病例的淋巴结总肿瘤体积(GTV-N)和临床目标体积(CTV)。在阶段2中,指示相同的临床医生遵循轮廓描绘方案以重新描绘另一组目标体积的轮廓。使用骰子相似系数(DSC)分析和定量靶体积的变化。
结果:16位临床医生提供了常规卷,而十个提供了每个病例的常规和方案卷。常规GTV-N的IOV在所有情况下都是最引人注目的,最小的DSC为0.37(95%CI0.32-0.42),其次是CTV,而GTV-T表现出较高的一致性。遵循协议后,GTV-N的最小DSC提高到0.64(95%CI0.45-0.83,P=0.005),但GTV-T和CTV的DSC在大多数情况下保持不变。
结论:观察到目标体积描绘的变异性,但是使用强制性干预措施可以显着减少和控制。
OBJECTIVE: To investigate the interobserver variability (IOV) in target volume delineation of definitive radiotherapy for thoracic esophageal cancer (TEC) among cancer centers in
China, and ultimately improve contouring consistency as much as possible to lay the foundation for multi-center prospective studies.
METHODS: Sixteen cancer centers throughout
China participated in this study. In Phase 1, three suitable cases with upper, middle, and lower TEC were chosen, and participants were asked to contour a group of gross tumor volume (GTV-T), nodal gross tumor volume (GTV-N) and clinical target volume (CTV) for each case based on their routine experience. In Phase 2, the same clinicians were instructed to follow a contouring protocol to re-contour another group of target volume. The variation of the target volume was analyzed and quantified using dice similarity coefficient (DSC).
RESULTS: Sixteen clinicians provided routine volumes, whereas ten provided both routine and protocol volumes for each case. The IOV of routine GTV-N was the most striking in all cases, with the smallest DSC of 0.37 (95% CI 0.32-0.42), followed by CTV, whereas GTV-T showed high consistency. After following the protocol, the smallest DSC of GTV-N was improved to 0.64 (95% CI 0.45-0.83, P = 0.005) but the DSC of GTV-T and CTV remained constant in most cases.
CONCLUSIONS: Variability in target volume delineation was observed, but it could be significantly reduced and controlled using mandatory interventions.