Comparing Irinotecan With Etoposide When Combined With Platinum In Patients With Previously Untreated Extensive-stage Small Cell Lung Cancer:A Meta-analysis

Objective: Etoposide or irinotecan combined platinum regimen is the standard first-line therapy for extensive-stage small cell lung cancer(ES-SCLC).Some researches exhibited that irinotecan combined platinum regimen may have survival benefits.It is still debated whether irinotecan combined platinum regimen can replace the etoposide combined platinum regimen as the first-line chemotherapy for ES-SCLC.We performed a meta-analysis to compare these regimens as first-line chemotherapy for extensive-stage small cell lung cancer in efficacy and safety.Methods: The Cochrane Library,Pub Med,Embase electronic databases were used to perform an electronic search,and the Physician Data Q uery registry of C linical Trials.gov(http://clinicaltrials.gov)was searched to ide ntify ongoing studies.To avoid publication bias,the search results were limited to randomized controlled trial,and no language,publishing time or other limitations.The trials searched were evaluated for eligibility and quality.Data were abstracted and analyzed by using Statistical Methods programmed in Review Manager Version 5.3.The HR was used for progression free survival(PFS)and overall survival(OS).For dichotomous data,relative risk(RR)was used for CR,PR,ORR,DRR,1-year survival,2-year survival,and adverse event data.Results: Eight randomized controlled trials(2089 patients)were included according to the inclusion and exclusion criteria.We found that an IP regimen could significantly improve OS(HR = 0.84;95% CI 0.77-0.92;P = 0.0002),but differences in PFS,CR,PR,ORR,DCR and 1-year survival rate were not statistically significant as compared to an EP regimen in ED-SCLC patients.IP regimen led to a higher PFS as compared to EP regimens,particularly for Asian patients and had a statistical significance(HR=0.69 95% C I,0.49-0.98;P=0.04)as the subgroup analysis.Meanwhile,Patients who were treated with an IP regimen experienced grade 3-4 diarrhea more frequently,and experienced fewer hematologic toxic events.Conclusion: We concluded that IP regimens may substitute for EP regimens as the first-line treatment for ED-SCLC patients,particularly for Asian patients who have a good performance status.For the sake of alleviating the adverse effects,we should perform the testing of the gene polymorphism of UGT1A1 *28 and UGT1A1*6.