408P - Radiation-induced lung toxicity and tumor progression in patients with non-small-cell lung cancer

Abstract

Background: Lung cancer is the leading cause of cancer death worldwide, and non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancer cases. Radiotherapy is an important treatment modality, approximately two-thirds of lung cancer patients receive radiation therapy (RT) during the course of treatment with either definitive or palliative intent. However, radiation-induced lung toxicity, including radiation pneumonitis (RP) and subsequent lung fibrosis limits the therapeutic ratio and can also complicate quality of life for survivors. Meanwhile, most treated individuals develop disease recurrence that affects disease prognosis. Here we investigate the relationship between the radiation-induced lung toxicity and tumor progression in patients with non-small-cell lung cancer. Methods: From Jan. 2009 to Dec. 2014, patients who received definitive radiation therapy (RT) for stages I-III lung cancer and who were diagnosed with radiation-induced lung toxicity (RILT) were retrospectively analyzed. The primary endpoint was tumor progression (local progress and distant metastasis). The effect of RILT on overall survival (OS) and progression-free survival (PFS) of patients with different clinico-pathological factors were evaluated with Kaplan-Meier method and log-rank test. Results: Among 91 patients, tumor progression was observed in 73 (80%). RILT effect on the OS between no tumor progression and tumor progression (median OS 40.6 months versus 36.3 months, P < 0.01), and the PFS indicates that the patients with no tumor progression have a longer median progression-free survival (median PFS 26.7 versus 22.7 months, P < 0.01). Then RILT was divided into two grades, the severe RILT (60%) and mild RILT (40%), and stratified analysis revealed that the mild RILTs resulted in a favorable prognosis compared with the severe RILT (median PFS 39.5 v 22.7 months, P = 0.022). Meanwhile, through further analysis we found a close connection between the degrees of RILT and tumor progression (local progress and distant metastasis) (P < 0.001). Conclusions: Radiation-induced lung toxicity (RILT) is linked to tumor progression in patients with non-small-cell lung cancer received definitive radiation therapy (RT). Legal entity responsible for the study: Nannan Wang Funding: None Disclosure: All authors have declared no conflicts of interest.