Pre-Diagnosis Air Pollution Exposure and Survival in Stage 1A NSCLC: A U.S. Cohort Study

Background: Ambient air pollution is a modifiable determinant of lung cancer survival, affecting early-stage Non-Small Cell Lung Cancer (NSCLC) incidence and mortality. Methods: This retrospective cohort study examined the association of all-cause mortality and exposure to air pollution among stage 1A NSCLC-treated patients from the U.S. National Cancer Registry from 1988 to 2015. The Cox hazard model and Kaplan-Meier survival plots were provided. Air pollutants were included separately and together in the models, accounting for spatiotemporal weather variability affecting air pollution exposure levels pre and post-diagnosed lung cancer. Results: NO2 (above median sample mean=25.66 ppb, 12.97 ppb below median), SO2 (above median sample mean=3.98 ppb, 1.81 ppb below median), and CO (above median sample mean=1010.84 ppb, 447.91 ppb below median) air pollutant levels and weather conditions were calculated for county-day units. The median survival months for those exposed to above median NO2 is 27 months (SD=17.61 months) and 30 months (SD=15.93 months) for those exposed to below median. Multipollutant analyses indicated that an average monthly NO2 increase of 1 part per billion (ppb) in the county of NSCLC diagnosis was associated with 4%, 6%, and 9%; SO2 were 16%, 17%, and 17%; 53%, 51%, and 42% for CO increase in the all-cause mortality hazard rate one, three, and five years after diagnosis, respectively. Conclusion: It is vital to implement environmental policies that control emissions to reduce preventable deaths in stage 1A NSCLC patients with adenocarcinoma or squamous cell carcinoma histology types who reside in metropolitan areas.