Abstract: Objective The aims of this study were to investigate the correlation between the early stage of severe granulocytopenia and the curative effect on clinical prognosis of chemotherapy in the first-line EP regimen of small cell lung cancer(SCLC). Methods A retrospective study analysis of 82 cases of first-line EP chemotherapy in patients with SCLC was collected clinical data,according to the time of patients with severe neutropenia.Patients were divided into two groups i.e.early-onset group(the first two cycles appeared Ⅲ-Ⅳ neutrophil decline)and non-early-onset group(Ⅲ~Ⅳ neutropenia did not appear or three cycles and later).The main indicators for the observation were objective response rate(ORR),disease control rate(DCR),time to progression(TTP)and overall survival(OS).Kaplan-Meier method and Log-rank test were used to analyze univariate survival and Cox proportional hazards model to analyze multivariate survival. Results The effective rates of chemotherapy were 81.8% and 75.5%(P=0.499),and DCRs were 97.0% and 95.9% in early-onset and non-early-onset groups,respectively(P＞0.05).The median survival time was 10.4 months and 6.9 months in early-onset and non-early-onset groups,respectively(P=0.001).The median OSs were 22.4 months and 16.0 months in early-onset and non-early-onset groups,respectively(P=0.023).Multivariate survival analysis revealed that smoking index,number of chemotherapy cycles,chest radiotherapy and early-onset severe neutropenia were independent prognostic factors for SCLC(P＜0.05). Conclusion Chemotherapy-related loss of early severe neutropenia correlates with the efficacy of chemotherapy in SCLC and is an independent predictor of prognosis in SCLC.

Key words: Small cell lung cancer, Chemotherapy, Neutropenia, Prognosis