【作者】 陈骏；

【导师】 刘云鹏；

【作者基本信息】 中国医科大学 ， 肿瘤学， 2009， 博士

【摘要】 小细胞肺癌的预后因素目的1.大约百分之三十至四十的小细胞肺癌(SCLC)首次临床治疗时处于局限期,他们的中位生存期是15至20个月,大约百分之二十至四十的局限期小细胞肺癌(LS-SCLC)患者生存期超过两年,这在小细胞肺癌已被认为是“长期”生存。在过去的几十年,在北美和其他国家,局限期小细胞肺癌患者的存活率已被证实有了一定程度的改善。综合疗法是治疗局限期小细胞肺癌的标准治疗方法,并能显著改善患者的生存。本研究试图探讨和界定已知及尚有争议的,影响局限期小细胞肺癌预后因素的重要性,特别是吸烟状况和治疗方案。2.在不同类型的肺癌中,小细胞肺癌预后最差;联合放疗和化疗是标准的治疗方法。然而,不同的治疗方法结果也各有不同;治疗过程中化疗药物的代谢速度和DNA损伤的修复,被认作是不同的原因。本研究在谷胱甘肽合成和DNA修复途径中,选择基因单核苷酸多态性标记的方法,以便进一步核实它们与小细胞肺癌患者生存的关系。材料和方法1.本项研究涉及1997年至2008年,在美国梅奥医院(Mayo Clinic),284例局限期小细胞肺癌患者的诊治和后续跟踪,分短期生存者(＜2年,163例)和长期生存者(＞2年,121例)两组,我们还根据患者自己的烟龄、确诊后戒断的时间等细分了五组。五组界定如下:(1)从未吸过烟及确诊前10年或更早就已戒烟,(2)戒烟3-9年,(3)戒烟1-2年,(4)确诊后戒烟,和(5)从未戒烟。吸烟的“剂量”或“强度”被定义为自我报告的每天包数(PPDs),以及吸烟史的长短及总的包/年数。按年龄,性别,吸烟史,体力状况评分(PS),肿瘤复发或进展以及治疗情况,用Cox比例风险模型等项为基础进行评估。2.用248例混合性(局限期加广泛期)小细胞肺癌(确诊时间为1997-2006年间)血液DNA,从49种基因进行单核苷酸多态性标记、谷胱甘肽和DNA修复途径的分型。我们选择了与谷胱甘肽途径相关的基因,即选择包括同工酶和膜结合转运蛋白相关的29种基因。从DNA修复途径选择了另外的20个基因,这些基因与肺癌或其他癌症的生存和治疗反应相关。使用Illumina GoldenGate custompanel定制设计基因型,即419个为单核苷酸多态性标记,其中,267个来自谷胱甘肽途径,152个来自DNA修复途径。基因转型率是由每一个单核苷酸多态性与Hardy-weinberg平衡评估后获得的。单核苷酸多态性与基因转型率低于95%,或不在Hardy-weinberg平衡中,或在本研究群体中是单一的情况,则不进行进一步分析。患者研究的描述性分析:由生存状态为指标对248例患者的临床特点进行了首次总结。为判断在基本遗传分析中是否需要变量调整,对临床变量是否与生存有关进行了评估。对每个变量我们都获得了卡普兰曲线,并使用Cox比例危险率回归方式。本研究在调整常规临床变量后,对患者生存进行了包括单核苷酸多态性、全基因以及单体型水平的相关分析。实验结果1.284例局限期小细胞肺癌患者的人口统计数据和临床资料,显示了两个对照组的年龄、性别、戒烟状态、复发或进展情况,化疗开始后一个月,加上放疗和预防性脑照射有很显著的生存差别。年轻患者的寿命更有可能超过两年。更多的妇女比男子存活期大于两年。两组间吸烟状况和年吸烟量无显著差异,然而戒烟显示出对于生存的积极影响。局限性小细胞肺癌患者的复发或进展缩短了治疗后的生存期。而两组间早期或晚期胸部放射治疗无显著差异,确诊后一个月就开始化疗时,更多的病人生存期超过两年。联合放化疗和预防性脑照射能改善预后,但不同的化疗组合对生存并没有表现出显著的影响。主要结果如下:(1)虽然在确诊出小细胞肺癌时,患者吸烟(既往或现吸烟者),和吸烟强度(包/年)都不是显著的生存预测项,相比继续吸烟者(没有戒烟),确诊后戒烟的病人死亡风险减少了50%(HR=0.50,95%CI0.36-0.77)。(2)胸部放射治疗和铂类药物为基础的化疗可显著延长生存的时间,但开始化疗或放射治疗的时间(确诊后一个月内或之后)对生存时间没有显著影响。(3)其他已知因素调整后,体力状况较差并不预示生存期更短。2.在成功的375个单核苷酸多态性基因分型中,在调整年龄、性别、肿瘤分期、治疗方式和吸烟史后,21个明显与生存有关。这21个多态单核苷酸,位于11个基因中(7个在谷胱甘肽、4个在DNA修复途径中)。依据所观察到的核苷酸多态性相关性,用全基因分析确认了11个基因中的3个:即GSS、ABCC2和XRCC1;经单体型分析,确定这三个基因的单体型组合以及基因所在位置。进一步分析确定了在GSS和ABCC2的几个单体型均与小细胞肺癌整体存活率显著正相关;而在XRCC1,我们数据库的5个单核苷酸多态性中,一个(rs100158)与增加小细胞肺癌的生存期相关,而另一个(rs2854510)与降低小细胞肺癌的生存期相关。结论1.这项研究证明了继续吸烟对生存的负面影响。因此,临床医师和所有医务工作者应大力鼓励患者戒烟。2.谷胱甘肽途径和DNA修复的基因遗传变异与小细胞肺癌治疗的结果有关。更多还原

【Abstract】 Objective1.Approximately 30 to 40 percent of small cell lung cancer(SCLC)is imited-stageSCLC(LS-SCLC)at first clinical presentation.The median ranges of survival for LS-SCLC are 15 to 20 months.Approximately 20 to 40 percent of LS-SCLC patients can survive longer than two years,which is considered as“long-term”survival in SCLC.In the last a few decades,a modest yet significant improvement of the survival rate of LS-SCLC has been shown in North America and other countries.Combined modality therapy is the standard care for limited stage-small cell lung cancer(LS-SCLC)and has led to a significant improvement in patients’ survival.This study sought to investigate and define the importance of prognostic effects of known and controversial factors especially the impact of smoking status and treatment strategies.2.Small cell lung cancer(SCLC)carries the worst prognosis among various types of lung cancer.Combined radiation and chemotherapy is the standard of care;however, outcomes from the treatment vary.Metabolic rate of chemotherapy agents and DNA repair capability may be partly responsible for this variation in treatment response.This study selected tagSNPs from genes in the glutathione synthesis and DNA repair pathways to test their association with survival in patients with SCLC.Materials and Methods1.A total of 284 patients with LS-SCLC diagnosed and prospectively followed from 1997 to 2008 at Mayo Clinic.Two groups in this cohort,short-term survivors(＜2 years,n=163)and long-term survivors(＞2 years,n=121),we also subcategorized patients according to their duration of smoking abstinence at the time of diagnosis and during follow-up.Five groups were defined as follows:(1)quit greater than or equal to 10 years prior to diagnosis or never smokers,(2)quit for 3-9 years,(3)quit for 1-2 years,4)quit at or after diagnosis,and(5)did not quit.The cigarette“dose”or “intensity”categories were defined as self-reported packs per day(PPDs)as well as the total number of pack-years of smoking history,were assessed on the basis of age, gender,smoking history,performance score(PS),tumor recurrence or progression,and treatment using Cox proportional hazards models.2.Blood DNA from 248 patients with primary SCLC(diagnosed 1997-2006)was genotyped for tagSNPs from 49 genes in glutathione and DNA repair pathways.We included genes in the glutathione pathway as described previously.Twenty nine genes, including isozymes and membrane bound transporter proteins,were selected.An additional twenty genes were selected from the DNA repair pathway following a review of the literature that reported association with treatment response or survival in lung or other cancers.Four hundred nineteen tagSNPs,267 from the glutathione and 152 from DNA repair pathway,were genotyped using a custom-designed Illumina GoldenGate panel.Call rates were obtained for each of the SNPs and Hardy-Weinberg equilibrium was assessed.SNPs with call rate less than 95%or not in Hardy-Weinberg equilibrium or monomorphic in this study population were excluded for further analysis. Clinical characteristics of the 248 patients were first summarized by vital status. Clinical variables were assessed on their association with survival in order to assess the need to be included as adjustment variables in the primary genetic analyses.We obtained Kaplan-Meier curves for each covariate,and performed a stepwise selection process using Cox proportional hazards regression.Association analyses with patient survival were performed at the single SNP,whole gene,and haplotype levels after adjusting for conventional clinical covariates.Results1.Age,sex,smoking cessation,recurrence or progression,chemotherapy started after one month,combined chemoradiotherapy,and PCI varied significantly between the two survival groups(TableⅠ).Younger patients were more likely to live longer than two years.More women survived greater than two years than men did.Smoking status and pack-years smoked were not significantly different between the two groups; however,smoking cessation showed a positive impact on survival.LS-SCLC patients with recurrence or progression during treatment had shorter survival.There was no significant difference for early or late TRT between the two groups,while more patients survived greater than two years when chemotherapy was initiated after one month of diagnosis.Combined chemoradiotherapy and PCI improved prognosis. Different chemotherapy combinations did not show significant impact on survival.(1) Although neither smoking status(former or current smokers) nor intensity (pack-years smoked) at the time of SCLC diagnosis were significant survival predictors, compared to continued smokers(who never quit smoking),patients who quit at or after diagnosis cut the risk of death by 50%(HR=0.50,95%CI 0.36-0.77).(2) Thoracic radiotherapy and platinum-based chemotherapy could significantly improve survival but the timing(within or after 1 month of diagnosis) of starting chemotherapy or radiation therapy did not.(3) After adjusting for other known factors, lower PS did not predict poorer survival.2.Among the 375 SNPs successfully genotyped,21 showed significant association with survival after adjusting for age,gender,tumor stage,treatment modalities,and smoking history.These 21 SNPs are located on 11 genes(7 in glutathione and 4 in DNA repair pathways).Whole-gene analyses confirmed three of the 11 genes:the GSS,ABCC2 and XRCC1 and haplotype analyses of these three genes identified haplotype combinations and genomic locations underlying the observed SNP associations.Further analyses identified several haplotypes within GSS and ABCC2 were significantly positive associated with overall survival of SCLC.And within XRCC1,among the 5 SNPs in our data,one is(rs100158) correlated with increased and another(rs2854510) is associated with decreased survival in SCLC.Conclusion1.This study demonstrated the negative impact of continued cigarette smoking on survival;therefore,clinicians and all care providers should strongly encourage smoking cessation at diagnosis of LS-SCLC.2.Genetic variation in genes involved in the glutathione pathway and DNA repair is associated with outcomes of SCLC after treatment.更多还原