The impact of age on the survival outcomes and risk of radiation pneumonitis in patients with unresectable locally advanced non-small cell lung cancer receiving chemoradiotherapy.

Background: Chemoradiotherapy is the recommended treatment for patients with unresectable locally advanced non-small cell lung cancer (NSCLC). This study aimed to determine the impact of age on the survival outcomes and risk of radiation pneumonitis (RP) in patients with unresectable locally advanced NSCLC. Methods: The data of patients with unresectable locally advanced NSCLC who were treated with radiotherapy (RT), sequential chemoradiotherapy, or concurrent chemoradiotherapy between January, 2013, and December, 2017, in our institution were retrospectively reviewed and analyzed. Student's t-test and.2 test were used to evaluate the differences between groups divided by optimal cutoff. Survival rates were calculated using the Kaplan-Meier method, and multivariate cox regression was performed to determine the prognostic factors for survival outcomes. Results: A total of 749 patients were included in this analysis. Based on the optimal cutoff, the patients were stratified into two age groups: <65 years old (the younger group, n=482) and >= 65 years old (the older group, n=267). The older group had more patients with poor Karnofsky Performance Score (KPS), squamous cell sarcoma (SCC), and IIIA stage than the younger group. The older patients were more likely to have received RT alone (40.1%) and less likely to have received concurrent chemoradiotherapy (cCRT) (26.6%) than the younger patients (8.1% and 54.8%, respectively, P<0.001). The median overall survival (OS) was 33 months (95% CI: 29-37 months) and 21 months (95% CI: 18-27 months) for the younger group and the older group, respectively (P<0.001). Multivariate Cox regression analysis showed that age had a significant independent association with OS (HR, 1.25; 95% CI: 1.01-1.55) after adjustment for covariates. The incidences of RP, symptomatic RP, and severe RP were similar between the two groups, but the incidence of fatal RP was higher in the older group (4.5% vs. 1.7%, P=0.039). Conclusions: The clinical characteristics of the older patients in our study differed from those of the younger patients, and the older patients were more likely to choose conservative treatment. OS was longer in the older patients and more cases of fatal RP occurred in the older group.