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Objective@#To 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.@*Methods@#The 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.@*Results@#Large 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.@*Conclusions@#Large 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.
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Objective To 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.Methods The 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.Results Large 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.Conclusions Large 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.
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Objective: To compare the efficacy of induction chemotherapy (IC) plus intensity-modulated radiotherapy (IMRT) with that of concurrent chemo-radiotherapy (CCRT) plus adjuvant chemotherapy (AC) for patients with loco-regionally advanced naso-pharyngeal carcinoma (NPC). Methods:Data of 240 patients with loco-regionally advanced NPC were reviewed. These patients were admitted to the Sun Yat-sen University Cancer Center between January 2004 and December 2008. Among the 240 patients, 117 under-went the IC+IMRT and 123 were treated with the CCRT+AC. The IC+IMRT group received a regimen including cisplatin and 5-fluoro-uracil (5-FU). The CCRT+AC group received cisplatin concurrently with radiotherapy and subsequently received adjuvant cisplatin and 5-FU. The survival rates of the patients were assessed by Kaplan-Meier analysis, and the survival curves were compared by Log-rank test. Multivariate analysis was conducted using Cox proportional hazard regression model. Results:The 5-year overall survival (OS), disease-free survival, distant metastasis-free survival, local relapse-free survival, and the nodal relapse-free survival were 78.0%versus 78.7%, 68.9%versus 67.5%, 79.0%versus 77.0%, 91.6%versus 91.0%, and 95.3%versus 93.7%in the IC+IMRT and CCRT+AC groups, respectively. The survival between the two groups exhibited no significant differences. Higher rates of Grades 3 to 4 nau-sea-vomiting (8.1%vs. 1.7%, P=0.023) and leukopenia (9.7%vs. 0.9%, P=0.006) were observed in the CCRT+AC group. Multivariate analysis revealed that N stage and age were significant prognostic factors for the OS of the patients with loco-regionally advanced NPC. Conclusion:The treatment outcomes of IC+IMRT and CCRT+AC were similar. Distant metastasis remained as the predominant mode of treatment failure.