Association of ambient air pollutants with risk of lung cancer subtypes and survival after diagnosis

Ambient fine particulate matter (PM2.5) air pollution is associated with lung cancer risk. However, less is known regarding air pollution associations with lung cancer subtypes, and it is unclear if air pollution plays a role in lung cancer survival. To address this, participants in the American Cancer Society's Cancer Prevention Study-II Nutrition cohort (n=122,442) were linked to residential annual concentrations of particulate matter and gaseous pollutants. Extended Cox regression was used to model time-varying pollutant exposures with risk of lung cancer by subtype and risk of death after diagnosis (hazard ratio per pollutant 5th %-mean difference 95% confidence interval). From 1992-2017, 4,282 lung cancers were diagnosed. PM2.5 was associated with lung cancer incidence (1.06 1.02-1.11) as were nitrogen dioxide, ozone, and sulfur dioxide (4-7% increase). PM2.5 was associated with all lung cancer subtypes whereas nitrogen dioxide was particularly associated with adenocarcinoma (1.07 1.00-1.14), and ozone with large cell carcinoma (1.13 0.97-1.33). Among 3,656 lung cancer patients with detailed diagnosis information, there were few associations with pollutant exposure in the past year and overall mortality or lung cancer death specifically. Sulfur dioxide was associated with lung cancer death among localized stage cancers (1.18 1.00-1.40), while coarse particulates were associated with lung cancer death in regional stage cases with elevated but not statistically significant findings in current smokers. Both particulate and gaseous air pollutants were associated with incident lung cancer subtypes. Recent air pollution exposure was associated with shorter survival after lung cancer for select groups only.