A Retrospective Study Of Extensive-stage Small Cell Lung Cancer

Objective:To study the survival among all extensive-stage small cell lung cancer (SCLC),patients who received first-line chemotherapy and second-line chemotherapy and analysis the influence factors of them; to study the differences of objective response rate, side effects and survival among different chemotherapy regimens and to study the role of radiotherapy in the treatment of extensive-stage SCLC.Methods:394patients who were diagnosed as extensive-stage small cell lung cancer from February2001to December2011hospitalized in Peking Union Medical College Hospital were collected. The patients who received second-line chemotherapy can be divided into6groups, namly group A(CE/EP regimen), group B(regimens containing TPT),group C(regimens containing CPT-11),group D(regimens containing TAX/DXL),group E(regimens containing IFO)and group F(other regimens). Objective response rate was evaluated by RECIST criteria and side effects were evaluated by WHO criteria. Kaplan-Meier method was used to calculate the overall survival (OS) and progress-free survival (PFS).x2test was used to analysis the differences of objective response rate and side effects and between different groups. Univariate analysis and COX regression analysis were used to detect the influence factors of survival.Results:In all394extensive-stage small cell lung cancer patients,369cases received chemotherapy and the other25cases didn’t;164cases underwent thoracic radiotherapy;91cases underwent cranial radiotherapy after brain metastasis;8cases received prophylactic cranial irradiation. The median OS of all extensive-stage small cell lung cancer was14.8months;1-year,2-year and5-year survival rates were58.9%,27.2%and7.8%respectively. Due to the results of univariate and COX multivariate analysis, OS of extensive-stage SCLC was closely associated with age(t=7.565, P=0.006), ECOG score(t=5.295, P=0.021),liver metastasis(t=21.247, P=0.000),bone metastasis(t=15.970, P=0.000) and chemotherapy (t=29.375, P=0.000); the mortality risk of patients who didn’t receive chemotherapy was4.919times higher than who received; the mortality risk of patients without liver, bone metastasis was reduced by approximately50percent. The first-line chemotherapy was mainly EP(DDP+VP-16)or CE(CBP+VP-16) regimens(accounting for82.8%),4～6cycles. The total response rate was53.4%, with CE/EP regimen56.4%and other regimen39.1%; the difference between the two regimens was statistically significant(χ2=6.39, P=0.012). The median OS and PFS in first-line chemotherapy were15.1months and7.5months,respectively; the OS of extensive-stage SCLC in the latest11years was not improved significantly. The OS in first-line chemotherapy was closely associated with chemotherapy effect(t=12.088, P=0.010), chemotherapy cycle number(t=14.057, P=0.001), recurrence time(t=24.952, P=0.000);PFS was relevant with chemotherapy curative effect(t=57.146, P=0.000), chemotherapy cycle number (t=22.423, P=0.000). The median OS in second-line chemotherapy were7.0months and was relevant with recurrence time(χ2=6.769, P=0.034). The median PFS in second-line chemotherapy were3.0months and was irrelevant with chemotherapy regimen and recurrence time. The differences of response rate,OS and PFS between sensitive relapse and resistant relapse were not statistically different(P=0.144; χ2=2.039, P=0.153; χ2=0.770, P=0.380),but the OS and PFS of patients who relapsed above6months after first-line therapy were sigficantly higher than the former two. If choose6months of PFS in first-line chemotherapy as the cutoff point, OS of the two groups had significant difference(χ2=5.542, P=0.019),but PFS and response rate didn’t. The differences of OS and PFS between six regimens in second-line therapy were not statistically different(χ2=1.491, P=0.914;χ2=6.133, P=0.293);the response rate was significantly different(x-=12.413, P=0.017); further comparison between each group was not different;as to side effects, the incidence of gastrointestinal reaction in group C was higher than any other group. The OS between thoracic radiotherapy group and non-thoracic radiotherapy group was statistically different(x2=6.617, P=0.010); the OS between PCI group and non-PCI group was not statistically different(P=0.148),but the PFS statistically different(P=0.033).Conclusion:The median OS of all extensive-stage SCLC was14.8months;1-year,2-year and5-year survival rates were58.9%,27.2%and7.8%respectively. The median OS and PFS in first-line chemotherapy were15.1months and7.5months,respectively. The OS of extensive-stage SCLC in latest11years was not improved significantly. The patients who are yonger than60-years old, with good KPS, without liver and bone metastasis have good prognosis. Patients should receive chemotherapy with first-line standard regimen(CE/EP regimen),but the second-line chemotherapy standard regimen was controversial. It’s beneficial to survival,if the effect of first-line chemotherapy is PR-CR and the proper chemotherapy cycle number is4-6cycles. It can prolong PFS but not OS if add chemotherapy cycle number. Traditional defining method of recurrence time exists some drawbacks; maybe it’s more effective if choose6months of PFS in first-line chemotherapy as the cutoff point. If general conditions of patients permits,they can receive thoracic radiotherapy and PCI, which benefits survival to some extent.