Survival Disparities in the Radiotherapeutic Management of Lung Cancer by Regional Poverty Level

Purpose This study evaluates regional poverty level-dependent differences in lung cancer (LC) survival, focusing on patients receiving radiation therapy (RT). Methods and materials The Surveillance, Epidemiology, and End Results (SEER) database was used to retrospectively identify patients diagnosed with LC between 2000 and 2009. Patients were divided into socioeconomic status (SES) quintiles, with quintiles 1 and 5 representing the highest and lowest SES cohorts, respectively. The Kaplan-Meier method with the log-rank test was used to compare overall survival (OS) from diagnosis between demographic and clinical factor levels. Multivariate (MVA) Cox proportional hazards regression was used to examine the association of quintile and mortality, adjusting for demographic and clinical factors. Results Compared to those not receiving RT, the univariate (UVA) results showed a higher mortality associated with receiving RT (HR:1.091; CI:1.081-1.102) while the MVA demonstrated a protective effect (HR:0.882; CI:0.873-0.891). The MVA revealed that men had higher mortality rates than women (HR:1.192; CI:1.180-1.203). Caucasians had a lower mortality rate as compared to African Americans (adjusted HR:0.932; CI:0.918-0.947) while Asians, Pacific Islanders, and Native Americans had the highest overall survival rates (adjusted HR:0.752, CI:0.734-0.771). Among the entire study population, quintile 2 (HR:1.059, CI:1.043-1.076), quintile 3 (HR:1.091, CI:1.075-1.108), quintile 4 (HR:1.094, CI:1079-1.110), and quintile 5 (HR:1.201, CI:1.181-1.221) reported increased mortality rates compared with quintile 1. This trend was also observed among those undergoing RT, with quintile 2 (HR:1.034, CI:1.010-1.059), quintile 3 (HR:1.045; CI:1.021-1.069), quintile 4 (HR:1.056; CI:1.033-1.080), and quintile 5 (HR:1.153; CI:1.124-1.183) demonstrating incrementally worse OS. Conclusions Upon accounting for age, gender, race, SES, and tumor stage, RT may provide a positive survival benefit among those who received treatment. Minimal differences existed among SES quintiles regarding diagnoses made by tumor stage or patients receiving RT. An incrementally worse OS rate was associated with increasing regional poverty level. This trend persevered among those receiving RT.