阳性淋巴结对数比对pN0期胸段食管鳞癌术后患者预后的评估价值

Predictive value of log odds of positive lymph nodes for the prognosis of patients with node- negative squamous cell carcinoma of the thoracic esophagus after radical esophagectomy

目的探讨阳性淋巴结对数比（LODDS）对pn0期胸段食管鳞癌术后患者预后的评估价值。方法回顾性分析2005年1月至2009年1月期间天津医科大学肿瘤医院食管肿瘤科行食管癌根治术并经病理诊断为pN0期胸段食管鳞状细胞癌的136例患者的临床病理及随访资料，采用受试者工作特征（ROC）曲线确定LODDS[LODDS=log（阳性淋巴结数＋0．5）／（阴性淋巴结数＋0．5）]影响患者预后的最佳截点值。应用Kaplan—Meier法绘制生存曲线，Log—rank检验进行生存分析。采用Cox比例风险模型确定患者预后的独立危险因素。结果136例患者男112例，女24例，年龄27-92岁，其中≥65岁者79例；食管肿瘤位于上、中、下段分别为8、115和13例；肿瘤直径≤3．5cm者70例，〉3．5cm者66例；肿瘤浸润深度pT1-2期者32例，pT3-4期者104例；肿瘤TNM分期，I期14例，Ⅱ期85例，Ⅲ期37例；均行R。食管癌切除和淋巴结清扫术。全组患者中位随访时间为44．2（4．4～98．4）月。5年总体生存率（OS）为43．2％，总体中位生存时间为48月。ROC曲线分析确定LODDS评估预后的最佳截点值为-1．2。将LODDS≤-1．2定义为LODDS1期，有99例患者（LODDS1期组），其中位生存时间为56．5月，5年累计OS为48．3％；将LODDS〉-1．2定义为LODDS2期，有37例患者（LODDS2期组），其中位生存时间为30．0月，5年累计OS为29．7％；两组患者5年OS比较，差异有统计学意义（χ2=4．980，P=0．026）。多因素预后分析表明：肿瘤复发（HR=0．627，95％C1：0．395～0．996，P=0．048）和LODDS〉-1．2（HR=1．853，95％C7：1．155～2．974，P=0．011）是影响患者预后的独立危险因素。结论对于淋巴结阴性的胸段食管鳞癌术后患者，LODDS分期具有预测预后的独特优势；LODDS〈-1．2（截点值）的患者具有较好的预后。

Objective To investigate the log odds of positive lymph nodes （LODDS） on the prognosis of patients with node-negative squamous cell carcinoma of the thoracic esophagus after radical esophagectomy. Methods Clinical data of 136 patients with node-negative squamous cell carcinoma of the thoracic esophagus after radical esophagectomy from January 2005 to January 2009 were retrospectively analyzed. LODDS was estimated using the calculation ： log （pnod＋0.5）/（tnod-pnod＋0.5）, in which pnod indicates the number of positive lymph nodes and tnod indicates the total number of lymph nodes retrieved. The best cut-off value for LODDS was identified by using the receiver operating characteristic （ROC） curve. Drawing of survival curves was employed with the Kaplan-Meier estimator,and survival rate was analyzed using Log-rank test. The Cox proportional hazard model was used to identify independent factors associated with prognosis. Results A total of 136 patients, including 112 males and 24 females, seventy-nine patients were 65 years or older （range 27-92 years）, and were included in the present study. Among them, the most cancer site was the middle third of the thoracic esophagus （115 cases）, followed by the lower third （13 cases）, and the upper third （8 cases）. There were 70 patients with tumor diameter ≤3.5 cm and 66 patients with tumor diameter 〉 3.5 cm. There were 32 patients with stage pT1-2, and 104 with stage pT3-4. The number of patients in TNM classification I , II and Ill was 14, 85 and 37, respectively. All the patients received radical esophagectomy with primary tumor resection and lymph node dissection. The median follow-up time was 44.2 months （range, 4.4 - 98.4 months）. Five-year overall survival rate was 43.2%, and the median total survival time was 48 months. ROC analysis showed that the appropriate cut-off value of LODDS was -1.2. There were 99 patients with LODDS≤1.2（LODDS1 stage）, 37 patients with LODDS 〉 -1.2 （LODDS2 stage）, the median survival time and 5-year survival rate were 56.5 months and 48.3% in patients with LODDS1 stage and 30.0 months and 29.7% in patients with LODDS 2 stage, respectively, with significant difference （χ2 =4.980, P= 0.026）. Multivariate analyses showed that recurrence （HR = 0.627, 95% CI：0.395 to 0.996; P=0.048） and LODDS 〉 -1.2（HR = 1.853; 95% CI： 1.155 to 2.974; P = 0.011 ） were the independent factors affecting the prognosis of patients. Conclusions For patients with node-negative squamous cell carcinoma of the thoracic esophagus after radical esophagectomy, LODDS stage has a unique prediction for prognosis, and patients with LODDS less than -1.2 （cut-off value） have a better prognosis.