Physics · Biology · Technique
Interobserver variations in the delineation of planning target volume and with orgagans at risk different contouring methods in intensity-modulated radiation therapy for nasopharyngeal carcinoma
Yinglin Peng, Wenzhao Sun, Wanqin Cheng, Haiqun Xia, Jijin Yao, Weiwei Xiao, Guanzhu Shen, Lin Yang, Shu Zhou, Jiaxin Li, Ying Guan, Shuai Liu, Xiaowu Deng
Published 2019-10-15
Cite as Chin J Radiat Oncol, 2019, 28(10): 762-766. DOI: 10.3760/cma.j.issn.1004-4221.2019.10.010
Abstract
ObjectiveTo assess the interobserver variations in delineating the planning target volume (PTV) and organs at risk (OAR) using different contouring methods during intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC), aiming to provide references for the quality control of multi-center clinical trials.
MethodsThe PTV and OAR of CT image of 1 NPC patient manually delineated by 10 physicians from 8 different radiation centers were defined as the " manual contour group" , and the OAR auto-contoured using the ABAS software and modified by the physicians were defined as the " auto+ manual contour group" . The maximum/minimum ratio (MMR) of the PTV and OAR volumes, and the coefficient of variation (CV) for different delineated contours were comparatively evaluated.
ResultsLarge variation was observed in the PTV and OAR volumes in the manual contour group. The MMR and CV of the PTV were 1.72-3.41 and 0.16-0.39, with the most significant variation in the PTVnd (MMR=3.41 and CV=0.39 for the PTVnd-L). The MMR and CV of the manually contoured OAR were 1.30-7.89 and 0.07-0.67. The MMR of the temporal lobe, spinal cord, temporomandibular joint, optic nerve and pituitary gland exceeded 2.0. Compared with the manual contour group, the average contouring time in the auto+ manual group was shortened by 68% and the interobserver variation of the OAR volume was reduced with an MMR of 1.04-2.44 and CV of 0.01-0.37.
ConclusionsLarge variation may occur in the PTV and OAR contours during IMRT plans for NPC delineated by different clinicians from multiple medical centers. Auto-contouring+ manually modification can reduce the interobserver variation of OAR delineation, whereas the variation in the delineation of small organs remains above 1.5 times. The consistency of the PTV and OAR delineation and the possible impact upon clinical outcomes should be reviewed and evaluated in multi-center clinical trials.
Key words:
Interobserver variation in delineation; Planning target volume; Organ at risk; Nasopharyngeal neoplasm/intensity-modulated radiation therapy
Contributor Information
Yinglin Peng
Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
Wenzhao Sun
Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
Wanqin Cheng
Department of Oncology, The Shunde Hospital of Southern Medical University, Shunde 528300, China
Haiqun Xia
Department of Radiation Oncology, Tungwah Hospital of Sun Yat-sen University, Dongguan 523110, China
Jijin Yao
Department of Radiation Oncology, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, China
Weiwei Xiao
Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
Guanzhu Shen
Department of Radiation Oncology, Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 510095, China
Lin Yang
Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
Shu Zhou
Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
Jiaxin Li
Department of Radiation Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
Ying Guan
Department of Radiation Oncology, Affiliated Cancer Hospital of Guangxi Medical University, Nanning 530021, China
Shuai Liu
Department of Radiation Oncology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou 510655, China
Xiaowu Deng
Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
