ABSTRACT
Objective:To investigate the selection of timing and prognostic factors of thoracic radiotherapy for small cell lung cancer (SCLC).Methods:Retrospective analysis of clinical data of 143 patients with limited-stage small cell lung cancer who were treated with platinum-based etoposide chemotherapy combined with non-synchronized thoracic radiotherapy from October 2014 to September 2016 in the Affiliated Hospital of Xuzhou Medical University.According to the timing of chest radiotherapy, they were divided into early radiotherapy group (71 cases after 2-3 cycles of chemotherapy) and 72 cases of late radiotherapy group (starting chest radiotherapy after 4-6 cycles of chemotherapy). Survival analysis, Log-rank test and Cox regression model were performed by Kaplan-Meier method for single factor and multi-factor analysis.Results:The median follow-up time of 143 patients was 24.0 months.Univariate analysis of patients' prognosis showed that there were significant differences in age, smoking, prophylactic brain irradiation, curative effect of initial chemotherapy and timing of chest radiotherapy (all P< 0.05). The results of multivariate analysis showed that smoking (95% CI: 1.068-2.557, P=0.024), prophylactic brain irradiation (95% CI: 0.348-0.955, P=0.033), initial chemotherapy effect (95% CI: 0.175-0.498, P<0.001), timing of chest radiotherapy (95% CI: 0.377-0.930, P=0.023) were independent factors affecting the total survival period.The results of grouping analysis showed that the total survival time and progression free survival time (PFS) of patients in different time of chest radiotherapy were significantly higher in the early radiotherapy group than in the late radiotherapy group ( P<0.05). Comparison of the total survival time and PFS of patients with different initial chemotherapy effects: the cumulative total survival time and progression free survival time of stable patients with different radiotherapy opportunities were 18.00 months and 14.00 months ( P=0.017) in the early radiotherapy group and late radiotherapy group, and the median progression free survival time was 8.00 and 7.90 months ( P=0.533). The median overall survival time was 26.00 months and 22.00 months, respectively ( P=0.010), and the median progression free survival time was 19.00 months and 17.00 months, respectively ( P=0.030). Conclusion:For patients with limited-stage small cell lung cancer who have been treated with platinum plus etoposide chemotherapy combined with non-synchronized thoracic radiotherapy, no matter how effective the initial chemotherapy is, chest radiotherapy should be started as soon as possible.