Comparison of interobserver variations in delineation of target volumes and organs-at-risk for intensity-modulated radiotherapy of nasopharyngeal carcinoma among physicians from different levels of cancer centers
10.3969/j.issn.1005-202X.2024.03.001
- VernacularTitle:不同级别肿瘤中心医师对鼻咽癌调强放疗靶区和危及器官勾画差异比较
- Author:
Meining CHEN
1
,
2
;
Yimei LIU
;
Yinglin PENG
;
Qiuying XIE
;
Jinping SHI
;
Rong HUANG
;
Chong ZHAO
;
Xiaowu DENG
;
Meijuan ZHOU
Author Information
1. 南方医科大学公共卫生学院放射医学系/国家药监局化妆品安全评价重点实验室/广东省热带病研究重点实验室,广东广州 510515
2. 中山大学肿瘤防治中心/华南肿瘤学国家重点实验室/广东省鼻咽癌诊治研究重点实验室,广东广州 510060
- Keywords:
nasopharyngeal carcinoma;
intensity modulated radiotherapy;
organ segmentation;
absolute volume difference ratio;
Dice similarity coefficient;
coefficient of variation
- From:Chinese Journal of Medical Physics
2024;41(3):265-272
- CountryChina
- Language:Chinese
-
Abstract:
Objective To assess inter-observer variations(IOV)in the delineation of target volumes and organs-at-risk(OAR)for intensity-modulated radiotherapy(IMRT)of nasopharyngeal carcinoma(NPC)among physicians from different levels of cancer centers,thereby providing a reference for quality control in multi-center clinical trials.Methods Twelve patients with NPC of different TMN stages were randomly selected.Three physicians from the same municipal cancer center manually delineated the target volume(GTVnx)and OAR for each patient.The manually modified and confirmed target volume(GTVnx)and OAR delineation structures by radiotherapy experts from the regional cancer center were used as the standard delineation.The absolute volume difference ratio(△V_diff),maximum/minimum volume ratio(MMR),coefficient of variation(CV),and Dice similarity coefficient(DSC)were used to compare the differences in organ delineation among physicians from different levels of cancer centers and among the 3 physicians from the same municipal cancer center.Furthermore,the IOV of GTVnx and OAR among physicians from different levels cancer centers were compared across different TMN stages.Results Significant differences in the delineation of GTVnx were observed among physicians from different levels of cancer centers.Among the 3 physicians,the maximum values of △V_diff,MMR,and CV were 97.23%±83.45%,2.19±0.75,and 0.31±0.14,respectively,with an average DSC of less than 0.7.Additionally,there were considerable differences in the delineation of small-volume OAR such as the left and right optic nerves,chiasm,and pituitary,with average MMR>2.8,CV>0.37,and DSC<0.51.However,relatively smaller differences were observed in the delineation of large-volume OAR such as the brainstem,spinal cord,left and right eyeballs,and left and right mandible,with average△V_diff<42%,MMR<1.55,and DSC>0.7.Compared with the differences among physicians from different levels cancer centers,the differences among the 3 physicians from the municipal cancer center were slightly reduced.Furthermore,there were also differences in the delineation of target volumes for NPC among physicians from different levels cancer centers,depending on the staging of the disease.Compared with the delineation of target volumes for earlier stage patients(stages I or II),the differences among physicians in the delineation of target volumes for advanced stage patients(stages III or IV)were smaller,with average △V_diff and DSC of 98.31%±67.36%vs 69.38%±72.61%(P<0.05)and 0.55±0.08 vs 0.72±0.12(P<0.05),respectively.Conclusion There are differences in the delineation of GTVnx and OAR in radiation therapy for NPC among physicians from different levels of cancer centers,especially in the delineation of target volume(GTVnx)and small-volume OAR for early-stage patients.To ensure the accuracy of multicenter clinical trials,it is recommended to provide unified training to physicians from different levels of cancer centers and review their delineation results to reduce the effect of differences on treatment outcomes.
