多排螺旋CT检查对食管胃结合部腺癌新辅助化疗后临床分期评估的应用价值

Application value of multi-detector computed tomography evaluating the clinical staging of adenocarcinoma of the esophagogastric junction after neoadjuvant chemotherapy

目的：探讨多排螺旋CT检查对食管胃结合部腺癌（AEG）新辅助化疗后临床分期评估的应用价值。方法：采用回顾性横断面研究方法。收集2016年1月至2018年4月北京大学肿瘤医院收治的46例行新辅助化疗AEG患者的临床病理资料。患者新辅助化疗前、新辅助化疗后手术前2周行多排螺旋CT检查，并根据冠状位测量和轴位公式法判断肿瘤中心与食管胃结合部（EGJ）交界线的距离；患者新辅助化疗后行胃癌根治性切除＋D2淋巴结清扫术，病理科医师复阅术后大体标本测量AEG的肿瘤中心与EGJ交界线的距离。按照美国癌症联合会（AJCC）第8版TNM分期系统确定新辅助化疗后临床T分期（ycT分期）、N分期（ycN分期）和病理学T分期（ypT分期）、N分期（ypN分期）。根据美国国立综合癌症网络 （NCCN）标准确定肿瘤退缩分级（TRG）。观察指标：（1）AEG新辅助化疗后CT检查情况。（2）AEG 新辅助化疗后临床分期情况。（3）AEG术后病理学检查情况。（4）AEG术后病理学分期情况。（5）AEG新辅助化疗后临床分期准确率。（6）AEG新辅助化疗前后CT检查图像变化与病理学反应的关系。计数资料采用绝对数或百分比表示，组间比较采用x2检验，等级资料比较采用非参数检验。结果：（1）AEG新辅助化疗后CT检查情况：46例AEG患者中，5例CT检查冠状位图像示肿瘤全貌及EGJ交界线，CT检查轴位图像示EGJ管壁增厚，病变全层不均匀强化，浆膜面不光滑；直接测量肿瘤中心与EGJ交界线距离均〈 2 cm，此5例均按食管癌分期。41例患者CT冠状位图像无法在一张图像中同时显示肿瘤全貌与EGJ交界线，CT检查轴位图像示EGJ管壁增厚，病变全层不均匀强化，浆膜面不规则形态；使用公式法计算为负值者27例，按食管癌分期，计算为正值者14例，按胃癌分期。（2）AEG新辅助化疗后临床分期情况：46例AEG患者中，ycT分期：ycT1期1例，ycT2期6例，ycT3期31例，ycT4a期6例，ycT4b期2例；ycN分期：ycN0期5例，ycN1期 14例，ycN2期23例，ycN3a期4例。（3）AEG术后病理学检查情况：46例AEG患者中，38例为腺癌，3例为腺癌伴印戒细胞癌，3例为腺癌伴神经内分泌癌，2例为腺癌伴鳞癌。46例AEG患者中，大体标本上可观察肿瘤中心与EGJ交界线距离，按胃癌分期14例，按食管癌分期32例。（4）AEG术后病理学分期情况：46例AEG患者中，ypT分期：ypT0期1例，ypT1期3例，ypT2期5例，ypT3期29例，ypT4a期7例，ypT4b期1例；ypN分期：ypN0期17例，ypN1期4例，ypN2期15例，ypN3a期9例，ypN3b期1例。46例AEG患者中，TRG 0级1例，TRG 1级3例，TRG 2级16例，TRG 3级26例；20例为肿瘤有退缩，26例为肿瘤无退缩。（5） AEG新辅助化疗后临床分期准确率：新辅助化疗后AEG ycT分期的准确率为78.3%（36/46），ycN分期的准确率为54.3%（25/46）。（6）AEG新辅助化疗前后CT检查结果与病理学反应的关系：46例AEG患者中，原发灶胃壁厚度缩小33例，胃壁厚度稳定13例。20例肿瘤有退缩患者中，17例原发灶胃壁厚度缩小，3例原发灶胃壁厚度稳定；26例肿瘤无退缩患者中，16例原发灶胃壁厚度缩小，10例原发灶胃壁厚度稳定。两者原发灶胃壁厚度比较，差异无统计学意义（χ^2=3.069，P〉0.05）。 46例AEG患者中，腹腔可疑淋巴结短径之和缩小31例，淋巴结短径之和稳定14例，淋巴结短径之和增大1例。20例肿瘤有退缩患者中，16例淋巴结短径之和缩小，4例淋巴结短径之和稳定；26例肿瘤无退缩患者中，15例淋巴结短径之和缩小，10例淋巴结短径之和稳定，1例淋巴结短径之和增大。两者淋巴结短径之和的变化情况比较，差异无统计学意义（Z=-1.629，P〉0.05）。3例患者新辅助化疗前后原发灶胃壁与淋巴结短径之和变化情况不一致：CT检查示原发灶胃壁厚度化疗后缩小，而淋巴结短径之和无变化；病理学分期为ypN0期而临床分期为ycN1期。结论：参照AJCC第8版TNM分期系统，结合CT检查冠状位测量及轴位公式法可较客观地测量肿瘤中心与EGJ交界线的距离，从而选择食管癌或胃癌分期系统，纠正Siewert Ⅱ型AEG T3期过分期，提高总体临床分期准确率。

Objective：To investigate the multidetector computed tomography （MDCT） evaluating the clinical staging of adenocarcinoma of the esophagogastric junction （AEG） after neoadjuvant chemotherapy. Methods：The retrospective crosssectional study conducted. The clinicopathological data of 46 AEG patients who were admitted to the Peking University Cancer Hospital between January 2016 and April 2018 were collected. All patients underwent MDCT before and after neoadjuvant chemotherapy and at preoperative 2 weeks, the distance between tumor center and boundary of esophagogastric junction （EGJ） was judged through coronal measured values and axial formula method. Patients underwent radical resection of gastric cancer ＋ D2 lymph node dissection after neoadjuvant chemotherapy, pathologists reviewed the distance between center of AEG and boundary of EGJ, T staging （ycT） and N staging （ycN） of clinical staging, T staging （ypT） and N staging （ypN） of pathological staging after neoadjuvant chemotherapy were determined according to TNM staging of American Joint Committee on Cancer （AJCC） （8th edition）, and tumor regression grading （TRG） was determined according to the criterion established by National Comprehensive Cancer Network. Observation indicators： （1） CT examination after neoadjuvant chemotherapy; （2） clinical staging after neoadjuvant chemotherapy; （3） postoperative pathological examination; （4） postoperative pathological staging; （5）accuracy of clinical staging after neoadjuvant chemotherapy; （6）relationship between imaging changes of CT examination and pathological reactions. Count data were described as absolute number or percentage, and comparisons among groups were analyzed by the chisquare test. Comparisons of ordinal data were analyzed by the nonparametric test. Results：（1） CT examination after neoadjuvant chemotherapy： 5 of 46 AEG patients, coronal images of CT showed whole tumor and boundary of EGJ, axial images of CT showed EGJ wall thickening, heterogeneous enhancement in all layers of lesions, and unsmooth serosal surface; the distance between tumor center and boundary of EGJ is less than 2 cm by direct measurement, 5 patients were confirmed as esophageal cancer staging. For 41 patients, the same coronal image of CT cannot showed whole tumor and boundary of EGJ, axial images of CT showed EGJ wall thickening, heterogeneous enhancement in all layers of lesions, and irregularshaped serosal surface; 27 patients whose calculated values were negative based on formula method used esophageal cancer staging, and 14 patients whose calculated values were positive used gastric staging. （2） Clinical staging after neoadjuvant chemotherapy： among 46 AEG patients, ycT staging： staging ycT1, ycT2, ycT3, ycT4a and ycT4b were respectively detected in 1, 6, 31, 6 and 2 patients; ycN staging： staging ycN0, ycN1, ycN2 and ycN3a were respectively detected in 5, 14, 23 and 4 patients. （3） Postoperative pathological examination： of 46 patients, 38, 3, 3 and 2 were respectively confirmed as adenocarcinoma, adenocarcinoma with signetring cell carcinoma, adenocarcinoma with neuroendocrine carcinoma and adenocarcinoma with squamous carcinoma. Of 46 patients, the distance between tumor center and boundary of EGJ can be observed in 14 patients by gastric cancer staging and 32 patients by esophageal cancer staging. （4） Postoperative pathological staging： ypT staging： 1, 3, 5, 29, 7 and 1 patients were respectively detected in staging ypT0, ypT1, ypT2, ypT3, ypT4a and ypT4b; ypN staging： 17, 4, 15, 9 and 1 patients were respectively detected in staging ypN0, ypN1, ypN2, ypN3a and ypN3b. One, 3, 16 and 26 patients were confirmed as staging TRG 0, TRG 1, TRG 2 and TRG 3, including 20 patients tumor regression and 26 patients without tumor regression. （5） Accuracy of clinical staging after neoadjuvant chemotherapy： the accuracies of ycT staging and ycN staging were 78.3%（36/46） and 54.3%（25/46）.（6）Relationship between imaging changes of CT examination and pathological reactions： of 46 patients, 33 and 13 had respectively reduced and stable gastric wall thickness of primary lesion. Among 20 patients with tumor regression, 17 and 3 had respectively reduced and stable gastric wall thickness of primary lesion; of 26 patients without tumor regression, reduced and stable gastric wall thickness of primary lesion were respectively in 16 and 10 patients, with no statistically significant difference （x2=3.069, P〉0.05）. Of 46 patients, 31, 14 and 1 had respectively reduced, stable and increased sum of minor diameters of suspicious celiac lymph nodes. The reduced, stable and increased sum of minor diameters of suspicious celiac lymph nodes were detected in 16, 4, 0 of 20 patients with tumor regression and 15, 10, 1 of 26 patients without tumor regression, respectively, with no statistically significant difference （Z=-1.629, P〉0.05）. The changes of gastric wall thickness of primary lesion and sum of minor diameters of celiac lymph nodes before operation were not consistent to that after operation in 3 patients. CT examination showed gastric wall thickness of primary lesion reduced after chemotherapy, and sum of minor diameters of celiac lymph nodes didn＇t change; pathological staging and clinical staging were respectively in staging ypN0 and ycN1. Conclusion ：According to the TNM staging of AJCC （8th edition）, the distance between tumor center and boundary of EGJ is judged through coronal measured values and axial formula method and therefore determining to select staging system of esophageal cancer or gastric cancer, meanwhile, rectifying over T3 staging of Siewert Ⅱ gastric cancer and increasing overall accuracy of clinical staging.