Impact of underlying pulmonary diseases on treatment outcomes in early-stage non-small cell lung cancer treated with definitive radiotherapy

Purpose: Current guidelines recommend definitive radiotherapy for patients with medically inoperable early-stage non-small cell lung cancer (NSCLC). However, the impact of underlying pulmonary diseases on survival in those patients remains unclear. Methods: We retrospectively reviewed the medical records of 234 patients with stage I-II NSCLC treated with definitive radiotherapy alone at Samsung Medical Center between January 2010 and October 2017. We compared survival outcomes according to the presence of underlying pulmonary diseases, including chronic obstructive pulmonary disease (COPD), combined pulmonary fibrosis and emphysema (CPFE), and idiopathic pulmonary fibrosis (IPF). The control group in this study was stage I-II NSCLC patients who were non-COPD, non-CPFE, and non-IPF. Results: The median follow-up duration was 17 (range, 1-92) months. The median survival times of the control, COPD, CPFE, and IPF groups were 32, 49, 17, and 12 months, respectively (P<0.001). In a Cox proportional hazards analysis for factors associated with overall survival, patients with COPD showed a similar risk of death (adjusted hazard ratio [HR], 1.306; 95% confidence interval [CI], 0.723-2.358; P=0.376) compared to that of the control group, while patients with CPFE (adjusted HR, 3.382; 95% CI, 1.472-7.769; P=0.004) and IPF (adjusted HR, 4.061; 95% CI, 1.963-8.403; P<0.001) showed an increased risk of death. Conclusion: Definitive radiotherapy may be a tolerable treatment for early-stage NSCLC with COPD. However, poor survival in early-stage NSCLC patients with IPF or CPFE requires further study to identify and develop patient selection criteria as well as an optimal radiotherapy modality.