The effects of air pollution on mortality and clinicopathological features of esophageal cancer

This study aimed to estimate the associations between air pollution and esophageal cancer. In the ecologic cross-sectional study, correlation analyses were made between city-level mean concentrations of particulate matter less than 10 mu m in aerodynamic diameter (PM10), SO2, NO2 and city-level age-standardized mortality rates of esophageal cancer in Shandong Province, China. PM10 (p=0.046) and NO2 (p=0.03) both had significant linear correlations with esophageal cancer mortality rates. After introducing smoking as a risk factor in models of multiple linear regression analyses, PM10 was still an independent risk factor that increased esophageal cancer mortality rates. This study further compared clinicopathological features of 1,255 eligible esophageal squamous cell carcinoma patients by dividing them into different pollution level groups. There was statistically significant difference in gender distributions (p=0.02) between groups after subgroup analysis. Female patients accounted for a higher proportion in the high PM10 level group than in the low PM10 level group. It suggested that females were more sensitive to higher PM10 level pollution. The features that manifested the degree of malignancy of esophageal cancer, including primary tumor invasion, regional lymph nodes metastasis, histological grade, stage, lymph-vascular invasion and tumor size demonstrated no statistically significant difference between groups.