<p>Metal exposure has been identified as a risk factor for lung adenocarcinoma, yet the relationship between internal metal exposure and clinical characteristics reflecting tumor development has been underexplored. In this cohort study, we enrolled 285 consecutively admitted lung carcinoma patients and 118 age and sex-matched healthy participants, and determined the metal concentrations in paired plasma and blood cells by using a well-evaluated ICP-MS method. The associations between individual or combined metal exposures and tumor size, location, stage, or lymph node metastasis were evaluated by using univariable tests, logistic regression, restricted cubic spline analysis, weighted quantile sum, and Bayesian kernel machine regression. Patients with lung carcinoma and adenocarcinoma had higher levels of most plasma metals (Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Cd, Pb) and blood cell metals (Mg, Ca, Co). However, they had lower levels of Hg in plasma and blood cells, and lower Cu in blood cells. Our findings further revealed significant associations of Cu, As, Se, and Cd with tumor stage, Cu, As, and Hg with lymph node metastasis, and Ca, Ni, Zn, Se, and Cd with tumor size, respectively. No metals showed associations with tumor left or right locations. Notably, Cu, Cd, Ni, and Hg were associated with increased risk, while Ca, As, Se, and Zn exhibited negative associations, particularly in cases of advanced stage, lymph node involvement, or larger tumor sizes. Moreover, the collective metal exposure was significantly associated with tumor size, suggesting that moderate exposure, compared to low exposure, may be linked to tumor growth. These results indicate that variations in circulating metals are associated with development or progression of lung adenocarcinoma.</p>