Pollution and progression: Air quality and stage of lung cancer diagnosis across the U.S.

Abstract

8003 Background: Air pollution contributes to increased lung cancer incidence, but whether it accelerates tumor progression, resulting in more advanced stage at diagnosis, is not well understood. Understanding environmental and social factors influencing late-stage presentation can guide targeted prevention efforts. Methods: We identified primary lung cancer cases from the National Cancer Database (NCDB; 2010–2023) across 2,803 U.S. counties. Individual-level data were linked to county-level annual averages of PM₂.₅ (μg/m³) and NO₂ (ppb). Generalized estimating equation logistic models with county-level clustering assessed associations between chronic pollution exposure and odds of advanced-stage (III–IV vs. I–II) diagnosis, adjusting for median household income and educational attainment. Pollutants were z-score standardized (mean = 0, SD = 1) and summed to create a combined Pollution Burden metric. Effect modification by histology and socioeconomic status was tested. Results: Among 1,023,140 patients (mean age 68.5 ± 10.8 years; 51.3% female), 67.1% presented with advanced-stage disease. Each standard deviation increase in PM₂.₅ was associated with 4.8% higher odds of advanced-stage diagnosis (95% CI: 3.5–6.1%; p < 0.001; Table 1). In multi-pollutant models, PM₂.₅ remained significant (OR = 1.062, 95% CI: 1.047–1.076; p < 0.001), with combined pollution burden linked to a 3.1% increase in odds (95% CI: 1.5–4.7%; p < 0.001). Low-SES communities had higher advanced-stage rates regardless of pollution exposure (69.7% vs. 63.6%; p < 0.001), equating to approximately 6,100 excess annual diagnoses. Effects varied by histology, with small cell carcinoma showing the highest advanced-stage rate (91.2%), followed by adenocarcinoma (67.3%) and squamous cell carcinoma (58.6%). Conclusions: Higher PM₂.₅ exposure and lower socioeconomic status were independently associated with later-stage lung cancer diagnosis across over 1 million cases from 2,803 U.S. counties. Low-SES communities showed 6 percentage points higher advanced-stage rates irrespective of pollution levels. These findings highlight how environmental factors that may accelerate cancer progression and social barriers to accessing care can jointly delay early-stage diagnosis. Targeted pollution control and expanded lung cancer screening in underserved communities could reduce the burden of advanced-stage disease. Odds of advanced-stage lung cancer by air pollutant exposure. Pollutant Model Mean ± SD OR 95% CI Lower 95% CI Upper P-value PM₂.₅ (μg/m³) Single-pollutant 8.17 ± 1.58 1.048 1.035 1.061 <0.001 PM₂.₅ (μg/m³) Multi-pollutant 1.062 1.047 1.076 <0.001 NO₂ (ppb) Single-pollutant 6.93 ± 3.93 1.009 0.993 1.026 0.28 NO₂ (ppb) Multi-pollutant 0.978 0.963 0.994 0.007 Combined Burden Z_PM2.5 + Z_NO2 1.031 1.015 1.047 <0.001