【 摘要】 背景与目的 二线或三线使用吉非替尼治疗化疗后失败的非选择性晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）的近期疗效只有10%-20%，女性、不吸烟、腺癌及亚裔具有更多的生存优势。然而临床中很难遇到符合以上所有条件的患者，所以有必要在临床中探索一些新的可以预测吉非替尼二、三线治疗晚期NSCLC生存时间的因素以及这些因素之间的相互影响。 方法 对2005年3月-2010年3月在中国医学科学院肿瘤医院使用吉非替尼治疗的晚期NSCLC的临床资料和生存资料采用分类及回归树（classification and regression tree, CART）分析。 结果 127例患者的中位无肿瘤进展生存时间（progression-free survival, PFS）为8个月（95%CI: 5.8-10.2）。CART分析将一线化疗疗效及年龄分别作为第一级及次级划分位点，逐级获得3个终末亚组。生存时间最短的是一线化疗进展（progressive disease, PD）的患者，中位PFS仅为1个月（95%CI: 0.8-1.2），处于中间位置的为一线化疗中取得部分缓解（partial response, PR）或稳定（stable disease, SD）的患者，年龄<70岁患者的中位PFS为10个月（95%CI: 7.0-13.0），而生存时间最长患者的中位PFS为22.0个月（95%CI: 3.8-40.1），为一线化疗后PR或SD且年龄70岁的患者。 结论 一线化疗后PR或SD且年龄70岁的患者可以获得较长的生存时间，而化疗后进展的患者生存时间不佳。回归树分析可以找出既往被忽略的亚组患者，这对临床工作具有重要的指导意义，并将有利于今后开展相关的临床研究。

【 Abstract】 Background and objective It has been proven that gefitinib produces only 10%-20% tumor regression in heavily pretreated, unselected non-small cell lung cancer (NSCLC) patients as the second- and third-line setting. Asian, female, nonsmokers and adenocarcinoma are favorable factors; however, it is difficult to find a patient satisfying all the above clinical characteristics. The aim of this study is to identify novel predicting factors, and to explore the interactions between clinical variables and their impact on the survival of Chinese patients with advanced NSCLC who were heavily treated with gefitinib in the second- or third-line setting. Methods The clinical and follow-up data of 127 advanced NSCLC patients referred to the Cancer Hospital & Institute, Chinese Academy of Medical Sciences from March 2005 to March 2010 were analyzed. Multivariate analysis of progression-free survival (PFS) was performed using recursive partitioning, which is referred to as the classification and regression tree (CART) analysis. Results The median PFS of 127 eligible consecutive advanced NSCLC patients was 8.0 months (95%CI: 5.8-10.2). CART was performed with an initial split on first-line chemotherapy outcomes and a second split on patients’ age. Three terminal subgroups were formed. The median PFS of the three subsets ranged from 1.0 month (95%CI: 0.8-1.2) for those with progressive disease outcome after the first-line chemotherapy subgroup, 10 months (95%CI: 7.0-13.0) in patients with a partial response or stable disease in first-line chemotherapy and age <70, and 22.0 months for patients obtaining a partial response or stable disease in first-line chemotherapy at age 70-81 (95%CI: 3.8-40.1). Conclusion Partial response, stable disease in first-line chemotherapy and age ≥ 70 are closely correlated with long-term survival treated by gefitinib as a second- or third-line setting in advanced NSCLC. CART can be used to identify previously unappreciated patient subsets and is a useful method for dissecting complex clinical situations. Moreover, CART can be used to identify homogeneous patient populations in clinical practice and future clinical trials.