基于2013版颈部淋巴结分区指南的鼻咽癌Ⅴ区转移规律研究

Study of levelⅤmetastasis of nasopharyngeal carcinoma based on 2013 updated consensus guidelines of the neck node levels

目的分析鼻咽癌颈部淋巴结转移在2013版颈部淋巴结分区的分布特点,探讨2013版Ⅴ区影像学特征,为鼻咽癌颈部临床靶区勾画提供初步参考。方法回顾分析2012—2020年间可调阅鼻咽及颈部MRI、定位CT图像的鼻咽癌患者1110例,并参照2013版颈部淋巴结分区指南重新分区,分别对Ⅴa、Ⅴb、Ⅴc区淋巴结转移与其他淋巴结区做相关性分析。选取1例T1N0M0期鼻咽癌作为样本,参照Ⅴc区正常解剖结构及比例等,将Ⅴc区转移的淋巴结勾画于样本病例定位CT图像上,解析Ⅴc区转移淋巴结位置分布特点。结果患者中1004例(90.5%)符合颈部淋巴结转移诊断,最高转移率的前两位为Ⅶa区(74.7%)、Ⅱb区(70.7%)。多因素分析显示Ⅴa区淋巴结转移与Ⅱb、Ⅲ、Ⅴb和Ⅷ区相关(P=0.010、0.001、0.001、0.001、0.037),Ⅴb区淋巴结转移与Ⅲ、Ⅳa、Ⅴa和Ⅴc淋巴结转移相关(P=0.006、0.001、0.001、0.001),Ⅴc区淋巴结转移与Ⅳb、Ⅴb区相关(P=0.008、0.001)。出现28例Ⅴc区淋巴结转移,共统计Ⅴc区转移淋巴结38个,其中33个(86.8%)淋巴结中心点位于样本病例肩甲舌骨肌内侧(Ⅴc-1区),5个(13.2%)位于肩胛舌骨肌外侧(Ⅴc-2区)。结论建议鼻咽癌Ⅴ区淋巴引流区各个亚区参考相关性分开勾画,有相关性时勾画为中危淋巴引流区(CTVn2);CTV_(n2)包含Ⅴc时建议进一步细化,Ⅴc-2区只有在同侧Ⅴc-1区有淋巴结侵犯时才作为CTVn2勾画。

Objective According to 2013 updated consensus guidelines of neck node levels,the distribution characteristics of cervical lymph nodes of nasopharyngeal carcinoma(NPC)were analyzed,aiming to provide preliminary reference for the clinical target volume(CTV)delineation of level Ⅴ in NPC.Methods A total of 1110 patients pathologically diagnosed with NPC from 2012 to 2020 were retrospectively recruited for further analysis.All patients’MRI and contrast-enhanced CT simulation scan imageswere retrospectively reviewed,metastatic lymph nodes were mapped using the 2013 International Consensus Guidelines.Then,the correlation between Ⅴa,Ⅴb and Ⅴc metastatic lymph nodes and other lymph nodes was analyzed.An NPC case diagnosed with T1N0M0 was selected as the baseline standard for the normal anatomical structure and proportion of Ⅴc area.The metastatic lymph nodes in Vc were delineated on the CT simulation scan image of sample case,and the distribution characteristics of the metastatic lymph nodes inⅤc were analyzed.Results Among the 1110 patients,1004(90.5%)patients had lymph node metastases.The most common area of metastatic lymph node levels were level Ⅶa(74.7%)and level Ⅱb(70.7%),and the skip metastasis of lymph nodes was rare(1.0%).The multivariate analysis showed lymph node metastasis in level Va was correlated with levels Ⅱb,Ⅲ,Ⅳa,Ⅴb,and Ⅷ region(P=0.010,0.001,0.001,0.001,0.037).Lymph node metastasis in level Ⅴb was correlated with levelsⅢ,Ⅳa,Ⅴa and Ⅴc region(P=0.006,0.001,0.001,0.001).Lymph node metastasis in level Ⅴc was correlated with levels Ⅳb and Ⅴb region(P=0.008,0.001).There were 28 cases of lymph node metastasis in level Ⅴc.A total of 38 metastatic lymph nodes were counted in level Vc.Among them,33(86.8%)lymph nodes were located in the medial of the omohyoid muscle(Ⅴc-1 region),and 5(13.2%)were located in the lateral of the omohyoid muscle(Ⅴc-2 region).Conclusions This study reflects the principle of individualized CTV delineation,which is based on the levels of nodal spread in NPC patients.When correlation is observed among different level V,V should be delineated as the moderate risk lymphatic drainage(CTVn2).It is recommended to individualized delineate level Vc when the CTVn2 covers Vc.The Ⅴc-2 region should be delineated as CTV_(n2) only when there is nodal spread in the ipsilateral Ⅴc-1 region.