影响cN0胃癌患者无病生存期的CT影像特征研究

Analysis of disease free survival based on CT imaging features in patients with cN0 gastric cancer

目的探讨影响临床诊断无淋巴结转移(cN0)胃癌患者的无病生存期(DFS)的CT影像特征。方法回顾性收集2005年1月至2018年12月北京大学人民医院经术前CT诊断临床TNM分期为cT1~4N0M0的298例胃癌患者,所有患者接受胃癌根治术并术后随访。分析和记录CT影像特征,包括临床肿瘤分期(cT)、壁外血管侵犯(EMVI)、肿瘤位置、形态学分型及最大径。根据病理结果将患者分为pT1~2、pT3~4、pN0、pN1~3亚组,分别为148、150、135、163例。记录随访中的进展期事件和相应时间。DFS为手术至进展期事件发生的时间;若无进展期事件发生,DFS为手术至最后1次随访时间。使用Kaplan-Meier生存曲线和log-rank检验分析不同CT影像特征间患者3年累积DFS差异,运用Cox生存分析探讨影响cN0患者3年DFS的独立影像学危险因素,并采用log-rank检验在不同亚组内比较独立危险因素对3年DFS的影响。结果入组患者随访时间为36.0(14.9,59.3)个月。cT3~4和cT1~2胃癌患者3年累积DFS率分别为61.2%、85.6%,差异有统计学意义(χ^(2)=22.72,P<0.001)。EMVI阳性患者3年累积DFS率为46.3%,低于EMVI阴性患者(77.1%),差异有统计学意义(χ^(2)=21.34,P<0.001)。不同原发灶位置和形态学类型分组间DFS生存曲线差异均无统计学意义(χ^(2)=1.75、1.73,P=0.189、0.196)。肿瘤最大径≥3.4 cm组和<3.4 cm组间的3年累积DFS差异有统计学意义(χ^(2)=17.58,P<0.001)。Cox生存分析结果显示cT(HR=5.203,P=0.001)和EMVI(HR=1.971,P=0.025)是影响cN0胃癌患者3年DFS的独立危险因素。亚组分析结果显示,在4个亚组中EMVI对患者3年累积DFS的影响均有统计学意义(P<0.05);cT对患者3年累积DFS的影响在pT1~2、pN0、pN1~3亚组中均有统计学意义(P<0.05),而在pT3~4组中无统计学意义(χ^(2)=2.58,P=0.108)。结论cT及EMVI是影响cN0胃癌患者3年DFS的独立影像学危险因素。

Objective To explore CT imaging features related to disease-free survival(DFS)for gastric cancer(GC)patients with no clinical lymph node metastasis(cN0).Methods From January 2005 to December 2018,298 patients with GC were collected retrospectively in Peking University People′s Hospital.All the patients performed CT scanning before operation,and cT1-4N0M0 was defined by CT images.The clinical tumor stage(cT),extramural vessel invasion(EMVI),tumor morphological type,location and size were defined and recorded based on preoperative contrast-enhanced CT images.According to the pathological results,the patients were divided into pT1-2,pT3-4,pN0,and pN1-3 subgroups,with 148,150,135,and 163 cases,respectively.Progressive events and corresponding time were recorded during follow-up.DFS was defined as the time from radical operation to progressive events;if no progressive events occurred,DFS was defined as the time from radical operation to the last follow-up.The Kaplan-Meier curve and log-rank test were used to analyze the differences in cumulative DFS among patients with different CT imaging features,and Cox survival analysis was used to explore the independent CT imaging risk factors affecting DFS of cN0 patients.The log-rank test was used to test the effect of independent risk factors on cumulative DFS in different subgroups.Results The follow-up time of enrolled patients was 36.0(14.9,59.3)months.The 3-year cumulative DFS rates of cT3-4 and cT1-2 GC patients were 61.2%and 85.6%,respectively,and the difference of DFS was statistically significant(χ^(2)=22.72,P<0.001).The 3-year cumulative DFS rate of EMVI-positive patients was 46.3%,which was lower than that of EMVI-negative patients(77.1%),and the difference was statistically significant(χ^(2)=21.34,P<0.001).There was no significant difference in 3-year cumulative DFS between different tumor locations and morphological types(χ^(2)=1.75,1.73,P=0.189,0.196).The difference in 3-year cumulative DFS between the tumor maximal diameter≥3.4 cm and<3.4 cm groups was statistically significant(χ^(2)=17.58,P<0.001).On Cox survival analysis,cT(HR=5.203,P=0.001)and EMVI(HR=1.971,P=0.025)were independent risk factors for 3-year DFS in patients with cN0 GC.The results of subgroup analysis showed that the effect of EMVI on the 3-year DFS in pN0,pN1-3,pT1-2 and pT3-4 subgroups was statistically significant(P<0.05).The effect of cT on the 3-year DFS was statistically significant in pN0,pN1-3,and pT1-2 subgroups(P<0.05),but not in pT3-4 group(χ^(2)=2.58,P=0.108).Conclusion cT and EMVI defined on preoperative CT examination are independently prognostic factors of 3-year DFS for patients with cN0 GC.