基于CT的下咽癌淋巴结转移规律分析

Analysis of lymph node metastasis for hypopharyngeal carcinoma based on computed tomography

目的 分析下咽鳞癌淋巴结转移规律,指导临床靶区的准确勾画。方法 2014—2017年在山东省肿瘤医院初诊的下咽鳞癌患者123例。经电子喉镜以及头颈部CT检查确诊,根据CT诊断标准判断颈部淋巴结转移,计算颈部各组淋巴结转移率（LMR）。采用单因素方差分析和χ2检验分析LMR与原发灶关系。结果 123例下咽鳞癌原发灶来源于梨状窝101例（82.1%）,咽后壁15例（12.2%）,环后区7例（5.7%）。123例患者中颈部淋巴结转移104例（84.6%）,其中原发灶来源于梨状窝、咽后壁和环后区肿瘤的LMR分别为84.2%、93.3%和71.4%。颈部各组LMR：（1）梨状窝癌：同侧颈部Ⅰ a 0、Ⅰ b3.0%、Ⅱ a66.3%、Ⅱ b42.6%、Ⅲ46.5%、Ⅳ10.9%、Ⅴ5.0%、Ⅵ a2.0%、Ⅵ b7.9%、Ⅶ11.9%;对侧颈部Ⅰ a0、Ⅰ b0、Ⅱ a14.9%、Ⅱ b5.0%、Ⅲ3.0%、Ⅳ2.0%、Ⅴ0、Ⅵ a0、Ⅵ b3.0%、Ⅶ2.0%。（2）咽后壁肿瘤：同侧颈部Ⅰ a 6.7%、Ⅰ b6.7%、Ⅱ a66.7%、Ⅱ b46.7%、Ⅲ46.7%、Ⅳ20.0%、Ⅴ0、Ⅵ a13.3%、Ⅵ b33.3%、Ⅶ60.0%;对侧颈部Ⅰ a6.7%、Ⅰ b6.7%、Ⅱ a33.3%、Ⅱ b26.7%、Ⅲ20.0%、Ⅳ20.0%、Ⅴ0、Ⅵ a0、Ⅵ b13.3%、Ⅶ33.3%。（3）环后区肿瘤：同侧颈部Ⅱ a71.4%、Ⅱ b28.6%、Ⅲ14.3%、Ⅳ14.0%、Ⅴ14.0%、Ⅵ b14.3%;对侧颈部Ⅱ a14.3%,其余淋巴组未发现淋巴结转移。T1—T4期肿瘤平均转移2.4、1.9、2.2、3.3个淋巴组（P=0.023）。梨状窝癌、咽后壁肿瘤、环后区肿瘤平均转移2.2、4.5、1.6个淋巴组（P=0.000）。咽后壁受侵与Ⅶ组淋巴结转移差异有统计学意义（P=0.000）;环后区或食管入口受侵与Ⅵ组淋巴结转移差异有统计学意义（P=0.002、0.001）。结论 下咽鳞癌颈部淋巴结转移以同侧Ⅱ a、Ⅲ、Ⅱ b组最常见,Ⅰ组和Ⅴ组少见。咽后壁来源肿瘤Ⅶ组淋巴结转移率高达60.0%。环后区或食管入口受侵,Ⅵ组淋巴结转移风险增加。

Objective To explore the pattern of lymph node metastasis and provide guidance for the delineation of clinical target volume for patients diagnosed with hypopharyngeal squamous cell carcinoma （HSCC）. Methods A total of 123 patients who were initially diagnosed with HSCC by electrolaryngoscope and computed tomography （CT） of the head and neck in Shandong Tumor Hospital between 2014 and 2017 were recruited in this study. The lymph node metastasis was evaluated based on the diagnostic criteria of CT scan. The lymphatic metastasis ratio （LMR） at each node level was calculated. Analysis of variance（ANOVA） and χ2 test were used to analyze the relationship between LMR and primary tumors. ResultsAmong 123 patients,primary tumors were originated from the pyriform sinus （PS） in 101 cases （82.1%）,posterior pharyngeal wall （PPW） in 15（12.2%） and postcricoid （PC） in 7（5.7%）,respectively. The overall LMR was calculated as 84.6%（n=104）,in detail, 84.2% for patients with primary tumors originating from PS,93.3% for those from PPW and 71.4% for patients from PC,respectively. For PS-derived tumors, the ipsilateral neck LMR at the level Ⅰ a,Ⅰ b,Ⅱ a,Ⅱ b,Ⅲ,Ⅳ,Ⅴ,Ⅵ a,Ⅵ b,and Ⅶ was 0,3.0%,66.3%,42.6%,46.5%,10.9%,5.0%,2.0%,7.9%,and 11.9%,respectively, and 0,0,14.9%,5.0%,3.0%,2.0%,0,0,3.0%,and 2.0% for the contralateral neck. For PPW tumors,the ipsilateral neck LMR at the level Ⅰ a,Ⅰ b,Ⅱ a,Ⅱ b,Ⅲ,Ⅳ,Ⅴ,Ⅵ a,Ⅵ b,and Ⅶ was 6.7%,6.7%,66.7%,46.7%,46.7%,20.0%,0,13.3%,33.3%,and 60.0%,respectively, and 6.7%,6.7%,33.3%,26.7%,20.0%, 20.0%,0,0,13.3%,and 33.3% for the contralateral neck. For PC tumors,the ipsilateral neck LMR at the level Ⅱ a,Ⅱ b,Ⅲ,Ⅳ,Ⅴ and Ⅵ b was 71.4%,28.6%,14.3%,14.0%,14.0%,and 14.3%,respectively, and the LMR at the level Ⅱ a was 14.3% for the contralateral neck. No lymph node metastasis occurred in other lymph node levels. The mean levels of lymph node metastasis for the T1-T4 stage tumors were 2.4,1.9,2.2,3.3 with statistical significance （P=0.023）, and 2.2, 4.5 and 1.6 for patients with the tumors originated from PS,PPW and PC （P=0.000）.The PPW invasion was significantly correlated with the level Ⅶ metastasis （P=0.000）,and PC or esophageal invasion was intimately correlated with the level Ⅵ metastasis （P=0.002 and 0.001）. Conclusions The most common lymphatic metastasis includes ipsilateral neck Ⅱ a,Ⅲ,and Ⅱ b,whereas the level Ⅰ and Ⅴ are rarely observed. For PPW-derived tumors, the LMR at the level Ⅶ is up to 60.0%. The incidence of PC or esophageal invasion enhances the risk of level Ⅵ lymph node metastasis.