Does adding thoracic radiation therapy to systemic chemotherapy increase 1-year and 2-year overall survival in patients with extensive-stage small-cell lung cancer? meta-analysis.

Background: Lung cancer is the leading cause of cancer-related mortality worldwide. Approximately 15-20% of newly diagnosed individuals with primary lung cancer have small cell lung cancer, and more than 60% of patients have advanced-stage small cell lung cancer at the time of diagnosis. Patients with advanced-stage small-cell lung cancer may benefit from thoracic radiation therapy. This comprehensive meta-analysis was conducted to determine whether adding thoracic radiation to systemic chemotherapy increases 1-year and 2-year survival in patients with advanced-stage small-cell lung cancer.

Methods: The Science Direct, PubMed, Embase, and Wanfang databases were comprehensively searched from 1980 to 2022. The inclusion criteria for studies were as follows: (1) all patients had advanced-stage small cell lung cancer; (2) a group receiving thoracic radiation therapy combined with chemotherapy was compared with a group receiving only chemotherapy; and (3) 1-year and 2-year overall survival data were provided. Pooled relative risks (RRs) and risk differences (RDs) were calculated, publication bias was evaluated, and sensitivity analysis was conducted.

Results: Ten studies met the inclusion criteria. These studies included 922 patients (534 patients in the chemotherapy combined with thoracic radiation therapy (ChT/TRT) group and 388 patients in the chemotherapy (ChT) group). The results of the meta-analysis revealed that the addition of thoracic radiotherapy to chemotherapy increased the 1-year overall survival rate to 52%, whereas the 1-year overall survival rate was 32.2% when chemotherapy alone was used. The addition of thoracic radiotherapy to chemotherapy also increased the 2-year survival rate to 18.7%, compared with 10% in the ChT group. The ChT/TRT group had a significantly better 1-year overall survival rate than the ChT group, with a pooled RR of 1.61 (95% CI, 1.36-1.90, P < 0.00001) and a pooled RD of 0.2 (95% CI, 0.13-0.26, P < 0.00001). The ChT/TRT group also had a significantly better 2-year overall survival rate than the ChT group, with a pooled RR of 1.90 (95% CI, 1.34-2.68, P = 0.0003) and a pooled RD of 0.09 (95% CI, 0.05-0.13, P < 0.0001).

Conclusion: This study revealed that adding thoracic radiation therapy to chemotherapy increases both 1-year and 2-year survival in patients with extensive-stage small-cell lung cancer.