[First-line chemotherapy and its survival analysis of 394 patients with extensive-stage small cell lung cancer in a single institute].

BACKGROUND AND OBJECTIVE: Small cell lung cancer (SCLC) is the most malignant neuroendocrine tumor but highly sensitive to chemotherapy and radiotherapy. At present, the standard first-line chemotherapy regimen of extensive-stage SCLC is platinum combined etoposide regimen. However, most patients who receive first-line chemotherapy will relapse within one to two years. Once recurrent, it indicates poor prognosis. In this study, we analyzed the survival among all extensive-stage SCLC and patients who received first-line chemotherapy and determined prognostic factors.

METHODS: Total of 394 patients who were diagnosed as extensive-stage small cell lung cancer from February 2001 to December 2011 hospitalized in Peking Union Medical College Hospital were collected. Kaplan-Meier method was used to calculate the overall survival (OS) and progression-free survival (PFS). Univariate analysis and Cox regression analysis were used to detect the influence factors of survival.

RESULTS: The median OS of all extensive-stage small cell lung cancer was 14.8 months; 1-year, 2-year and 5-year survival rates were 58.9%, 27.2% and 7.8%, respectively. According to the results of univariate and Cox multivariate analysis, OS of extensive-stage SCLC was closely associated with age (P=0.006), ECOG PS (P=0.021), liver metastasis (P<0.001), bone metastasis (P<0.001) and chemotherapy (P<0.001). The mortality risk of patients who didn't receive chemotherapy was 4.919 times higher than that who received; the mortality risk of patients without liver, bone metastasis was reduced by approximately 50 percent. The first-line chemotherapy was mainly EP (DDP+VP-16) or CE (CBP+VP-16) regimens (accounting for 82.8%) with 4-6 cycles. The median OS and PFS in first-line chemotherapy were 15.1 months and 7.5 months, respectively. The result of Cox regression analysis indicated that OS in first-line chemotherapy was remarkably related to smoking history (P=0.041), liver metastasis (P<0.001), bone metastasis (P<0.001), chemotherapy cycle number (P<0.001); PFS was relevant with smoking history (P=0.003), liver metastasis (P=0.001), bone metastasis (P<0.001), chemotherapy cycle number (P<0.001). Thoracic radiotherapy was not an independent influence factor of OS and PFS in extensive-stage small cell lung cancer.

CONCLUSIONS: The patients who were younger than 60-year old, with good KPS, absence of liver and bone metastasis had better prognosis. Patients should receive chemotherapy with first-line standard regimen (CE/EP regimen). It was beneficial to survival if the effect of first-line chemotherapy was SD or PR-CR and the proper chemotherapy cycle number was 4-6 cycles. The role of thoracic radiotherapy in extensive-stage small cell lung cancer needed to be investigated further.