Prognosis, imaging characteristics, and clinicopathological features of heavy smokers with clinical stage I lung adenocarcinoma: a multicenter study.

Objective: This study aimed to elucidate the relationship between smoking extent and prognosis, imaging characteristics, and clinicopathological factors in patients with clinical stage I lung adenocarcinoma (c-stage I LDA).

Methods: We evaluated 2,285 patients who underwent surgical resection for c-stage I LDA between 2010 and 2018. Patients were classified into three groups based on the Brinkman Index (BI): never smokers (BI = 0), light smokers (0 < BI ≤ 600), and heavy smokers (BI > 600). Clinicopathological features and prognosis were analyzed according to smoking extent.

Results: Significant differences in overall survival (OS) were observed across the smoking groups. Heavy smokers exhibited more invasive imaging characteristics, including a larger solid proportion and a higher maximum standardized uptake value (SUVmax), compared to never and light smokers. In multivariable analyses, heavy smoking was significantly associated with poorer OS (hazard ratio [HR] 2.071, p < 0.001). In addition, older age (HR 1.111, p < 0 .001) and the presence of vascular invasion (HR 2.312, p < 0.001) were also associated with worse OS among heavy smokers.

Conclusions: Smoking extent was independently associated with poorer survival, larger solid tumor size, and higher SUVmax in patients with c-stage I LDA. Age and vascular invasion emerged as strong prognostic factors, particularly among heavy smokers.