Chinese never smokers with adenocarcinoma of the lung are younger and have fewer lymph node metastases than smokers

Abstract

Background Lung cancers arising in never smokers have been suggested to be substantially different from lung cancers in smokers at an epidemiological, genetic and molecular level. Focusing on non-small cell lung cancer (NSCLC), we characterized lung cancer patients in China looking for demographic and clinical differences between the smoking and never-smoking subgroups. Methods In total, 891 patients with NSCLC, including 841 with adenocarcinoma and 50 with squamous cell carcinoma, were recruited in this study. Association of smoking status with demographic and clinical features of NSCLC was determined, and risk factors for lymph node metastasis and TNM stage were evaluated using Multivariate logistic regression analysis. Results In patients with adenocarcinoma, never smokers showed a younger age at diagnosis (54.2 ± 12.7vs. 59.3 ± 9.4, padjusted<0.001), a lower risk for lymph node metastasis than smokers (7,6% vs. 19.5%, padjusted<0.001) and less severe disease as indicated by lower percentages of patients with TNM stage of III or IV (5.5% vs. 14.7%, padjusted<0.001 ). By contrast, these associations were not observed in 50 patients with squamous cell carcinoma. Multivariate logistic regression analysis showed that smoking status was a risk factor for lymph node metastasis (OR = 2.70, 95% CI: 1.39–5.31, p = 0.004) but not for TNM stage (OR = 1.18, 95% CI: 0.09–14.43, p = 0.896) in adenocarcinoma. Conclusion This study demonstrates that lung adenocarcinoma in never smokers significantly differ from those in smokers regarding both age at diagnosis and risk of lymph node metastasis, supporting the notion that they are distinct entries with different etiology and pathogenesis.

Lung cancer in never smokers (LCINS): development of a UK national research strategy

“…More recently, key studies have interrogated LCINS, drawing attention to the marked molecular differences between LCINS and ever smokers [79][80][81][82]. These studies have focused on adenocarcinoma, the dominant pathological subtype [83][84][85][86].…”

Pulmonary mucinous adenocarcinoma: An overview of pathophysiology and advancements in treatment

“…The etiology and risk factors of PMA align with those of other lung cancers, although research on this specific subtype is limited because of its rarity. Smoking is the most significant risk factor for lung cancers, including PMA [ 15 ]. The risk increases with smoking duration and intensity.…”