Does The Addition Of Thoracic Radiation Therapy To Systemic Chemotherapy Improve The One-year And Two-years Overall Survival In Patients With Extensive-Stage Small Cell Lung Cancer: A Meta-analysis

BackgroundWorldwide lung cancer is the main cause of cancer related death.Small cell lung canceraccounts for about15to20percent of newly diagnosed patients with primary lungcancer. Small cell lung cancer used to be one of the most aggressive kinds of cancer andmore than60%of the patients were presented with advanced disease when they werediagnosed. Thoracic radiation therapy is one of the treatment modality for extensive stagesmall cell lung cancer patients.To check whether the addition of thoracic radiotherapy to systemic chemotherapy willimproves the one-year and two-years survival in patients with extensive stage small celllung cancer, a comprehensive meta-analysis was performed.MethodsA comprehensive search of Science Direct, Pubmed, Embase, Wanfang Data from1982to2012was done and the studies met the following criteria were included in this metaanalysis:(1) all patients have extensive-stage small cell lung cancer,(2) comparing twogroups, one receiving thoracic radiation therapy combined with chemotherapy and theother group receiving only chemotherapy,(3) one-year and2-years overall survival datawere provided. Pooled relative risk (RR) and risk difference (RD) were calculated,publications bias was evaluated and sensitivity analysis was conducted. ResultsTen studies meeting the inclusion criteria were identified enrolling922patients,534patients were in the chemotherapy combined with thoracic radiation therapy group (ChT/TRT) and388patients were in the chemotherapy group (ChT).In this meta analysis I found that addition of thoracic radiation therapy to chemotherapyincreases the one year overall survival rate to52%as compared to32.2%when usingchemotherapy alone, the two years survival of18.7%also increased as compared to10%when using chemotherapy alone.For1-year overall survival, the ChT/TRT group was significantly better than the ChTgroup, the pooled RR was1.61for ChT/TRT group compared to ChT group(95%CI,1.36-1.90,P<0.00001) and the pooled RD was0.2for ChT/TRT group comparedto ChT group（95%CI,0.13-0.26,P<0.00001）.For2-years overall survival, the ChT/TRT group was significantly better compared toChT group, the pooled RR was1.90for ChT/TRT group compared to ChT group(95%CI,1.34-2.68,P=0.0003) and the pooled RD was0.09for ChT/TRT group comparedto ChT group（95%CI,0.05-0.13,P<0.0001)ConclusionThe findings in this study shows that the addition of thoracic radiation therapy tochemotherapy improves both1-year and2-years survival in patients with extensive-stagesmall cell lung cancer.