Clinical outcomes of 327 patients with extensive-stage small cell lung cancer treated with chemotherapy combined with or without thoracic radiation therapy

Abstract

Objective To evaluate the influence of thoracic radiation therapy (TRT) on the survival of patients with extensive-stage small cell lung cancer (ES-SCLC) after chemotherapy. Methods A retrospective review was conducted on patients with ES-SCLC who received chemotherapy±TRT from January 2007 to December 2012. Most patients received initial chemotherapy with carboplatin plus etoposide or chemotherapy with cisplatin plus etoposide. A total of 130 cases of patients (39.8%) underwent TRT. TRT was performed through intensive modified radiotherapy. The median thoracic radiation dose was 56 Gy(32-67 Gy), with 1.8-2.3 Gy per fractions. The Kaplan-Meier, Log Rank test, and Cox regression were used for survival analysis and identification of prognostic factors. Statistically significant difference was set at P<0.05. Results Overall, 327 consecutive patients were enrolled. The follow-up rate was 95.1%. Patients reaching complete response(CR), partial response(PR), and stable disease(SD) after chemotherapy accounted for 2.4%, 76.1%, and 21.4%, respectively. The median follow-up time for survival patients was 69 months. The median overall survival (OS) of the whole group was 13.7 months, and the median progression-free survival(PFS) was 9.3 months. These results showed that TRT significantly improved the OS and PFS of patients. The median OS was 20.0 and 11.4 months in the TRT and non-TRT groups, respectively. Correspondingly, their median PFS was 10.8 and 7.7 months, respectively. The two-, three-, and five-year OS were 42.5%, 27.8%, and 18.8% in the TRT group and 11.6%, 6.6%, and 3.5% in the non- TRT group, respectively (χ2=50.730, P<0.001). Stratified analysis indicated that TRT can increase the OS in all the subgroups when the participants were divided according to different brain metastasis statuses and responses after chemotherapy(CR+PR, SD). However, TRT cannot improve the PFS of patients with brain metastasis. TRT can significantly decrease the locoregional recurrence rate to 19.2% and that of the non-TRT group was approximately 75.6% (χ2=100.080, P<0.001). Conclusion TRT can significantly improve the OS and PFS and decrease the locoregional recurrence rate in all patients with ES-SCLC with different brain metastasis statuses and responses after chemotherapy. Key words: Lung neoplasms; Carcinoma, small cell; Radiotherapy; Chemotherapy; Currative effect