淋巴结转移率对Ⅱ~Ⅲ期胃癌根治术后病人预后的评估

Metastatic lymph node ratio to evaluate prognosis of patients with stage Ⅱ-Ⅲ gastric cancer after radical gastrectomy

目的:探讨胃癌病人淋巴结转移率分组界值及其对预后的评估。方法:回顾性分析2004年1月至2008年7月复旦大学附属中山医院392例行胃癌根治术,分期为美国癌症联合委员会(American Joint Committee on Cancer,AJCC)(第8版)Ⅱ~Ⅲ期的病人。利用X-tile软件进行淋巴结转移率的分组,评估淋巴结转移率与其他临床病理因素的相关性和对病人预后的评估。建立列线图预测模型,绘制校准曲线,与实际作比较。用Bootstrap法进行内部验证,计算一致性指数(C-index)评估模型准确性。结果:X-tile获得淋巴结转移率的最佳截断值为0.20(20%)和0.70(70%)。将淋巴结转移率分为1组(0~20%)、2组(21%~69%)和3组(70%~100%)。3组病人的生存差异有统计学意义(P<0.001)。单因素分析显示,淋巴结转移率、TNM分期、T分期、N分期、淋巴管浸润和年龄是影响预后的相关因素。多因素分析显示,淋巴结转移率、T分期、N分期、淋巴管浸润及年龄是影响预后的独立因素。分别以淋巴结转移率、TNM分期、淋巴管浸润及年龄绘制病人总体生存率的受试者操作特征曲线,其曲线下面积分别为0.699、0.667、0.587、0.561。采用淋巴结转移率、TNM分期、淋巴管浸润和年龄构建列线图预测模型,其C-index为0.707(95%CI:0.705~0.708)。校正曲线显示的1、3及5年预测生存率与实际相符。结论:淋巴结转移率是影响Ⅱ~Ⅲ期胃癌根治术后病人生存的独立危险因素。在判断Ⅱ~Ⅲ期胃癌根治术后病人预后时,淋巴结转移率是N分期的有效补充,可指导合理治疗。

Objective To study the metastatic lymph node ratio for grouping of gastric cancer patients and evaluate the prognosis. Methods A total of 392 patients of gastric cancer who underwent radical gastrectomy with stage Ⅱ-Ⅲ according to the American Joint Committee on Cancer(AJCC) 8th in Zhongshan Hospital of Fudan University from January 2004 to July 2018 were retrospectively analyzed. X-tile software was used to group patients based on the metastatic lymph node ratio. The correlation between metastatic lymph node ratio and other clinicopathological factors was made, and the evaluation of prognosis of patients was assessed. The nomogram model of prediction was established. Calibration curves were drawn, and comparison between the curves and data of patients was performed. Internal validation was done by the Bootstrap method. Concordance index(C-index) was calculated to test the accuracy of model. Results X-tile analysis showed that the best cut-off values were 0.20(20%) and 0.70(70%) of metastatic lymph node ratio. According to the cutoff values, the patients in this study were divided into 3 subgroups at metastatic lymph node ratio 1(0-20%), metastatic lymph node ratio 2(21%-69%), and metastatic lymph node ratio 3(70%-100%) with significant difference in survival statistically(P<0.001). Univariate analysis showed that metastatic lymph node ratio, TNM stage, T stage, N stage, lymphatic invasion, and age were related factors affecting prognosis. Multivariate analysis showed that metastatic lymph node ratio, T stage, N stage, lymphatic invasion, and age were independent factors affecting prognosis. Receiver operator characteristic curve of postoperative overall survival rates of patients were drawn using metastatic lymph node ratio, TNM stage, lympha-tic invasion and age, of which area under the curve were 0.699, 0.667, 0.587 and 0.561. The independent 4 risk factors were taken into account to construct nomogram prediction models. C-index was 0.707(95% CI: 0.705-0.708). The 1-, 3- and 5-year survival rate predicted by the nomogram were consistent with the actual data. Conclusions Metastatic lymph node ratio is an independent factor affecting the prognosis of radical gastrectomy for stage Ⅱ-Ⅲ gastric cancer. Metastatic lymph node ratio is an effective supplement to pathological N stage, which can direct reasonable treatment.