Background: Erlotinib is a targeted therapy drug for non-small cell lung cancer (NSCLC). It has been proven that, there was evidence of various survival benefits derived from erlotinib in patients with different clinical features, but the results are conflicting. The aim of this study is to identify novel predictive factors and explore the interactions between clinical variables as well as their impact on the survival of Chinese patients with advanced NSCLC heavily treated with erlotinib.
Methods: The clinical and follow-up data of 105 Chinese NSCLC patients referred to the Cancer Hospital and Institute, Chinese Academy of Medical Sciences from September 2006 to September 2009 were analyzed. Multivariate analysis of progressive-free survival (PFS) was performed using recursive partitioning referred to as the classification and regression tree (CART) analysis.
Results: The median PFS of 105 eligible consecutive Chinese NSCLC patients was 5.0 months (95%CI: 2.9-7.1). CART analysis was performed for the initial, second, and third split in the lymph node involvement, the time of erlotinib administration, and smoking history. Four terminal subgroups were formed. The longer values for the median PFS were 11.0 months (95%CI: 8.9-13.1) for the subgroup with no lymph node metastasis and 10.0 months (95%CI: 7.9-12.1) for the subgroup with lymph node involvement, but not over the second-line erlotinib treatment with a smoking history ≤35 packs per year. The shorter values for the median PFS were 2.3 months (95%CI: 1.6-3.0) for the subgroup with lymph node metastasis and over the second-line erlotinib treatment, and 1.3 months (95%CI: 0.5-2.1) for the subgroup with lymph node metastasis, but not over the second-line erlotinib treatment with a smoking history >35 packs per year.
Conclusions: Lymph node metastasis, the time of erlotinib administration, and smoking history are closely correlated with the survival of advanced NSCLC patients with first- to third-line erlotinib treatment. CART can identify previously unappreciated patient subsets and is advantageous for identifying homogeneous patient populations in clinical practice and future clinical trials.
背景与目的: 厄洛替尼是治疗非小细胞肺癌（non-small cell lung cancer, NSCLC）的靶向药物。已有研究表明具有不同临床特征的患者对厄洛替尼的生存获益存在差异，但结论并不一致。本研究将探索厄洛替尼治疗晚期NSCLC生存时间的预测因素以及这些因素的相互影响。
方法: 对2006年9月-2009年9月在中国医学科学院肿瘤医院使用厄洛替尼治疗的晚期NSCLC患者的临床及生存资料采用分类及回归树分析（classification and regression tree, CART）。
结果: 105例患者的中位无肿瘤进展生存时间（progressive-free survival, PFS）为5.0个月（95%CI: 2.9-7.1）。CART分析将淋巴结分期、厄洛替尼治疗时机及吸烟状况分别作为第一、二、三级划分位点，逐级获得4个终末亚组。生存时间较长的是无淋巴结转移或有淋巴结转移、厄洛替尼治疗≤二线并且吸烟≤35包年的两组患者，中位PFS分别为11.0个月（95%CI: 8.9-13.1）和10.0个月（95%CI: 7.9-12.1），而生存时间较短的是有淋巴结转移且厄洛替尼的治疗>二线或有淋巴结转移、厄洛替尼治疗≤二线并且吸烟>35包年的两组患者，中位PFS分别为2.3个月（95%CI: 1.6-3.0）和1.3个月（95%CI: 0.5-2.1）。
结论: 是否存在淋巴结转移、厄洛替尼治疗时机以及既往吸烟状况是影响厄洛替尼治疗PFS的主要因素。CART可以找出既往被我们忽略的亚组患者，有利于为临床实践及今后临床研究找到同质性的患者群体。