Prognostic Value of Ki-67 and 18F-FDG PET/CT SUVmax in Non–Small Cell Lung Cancer

Background Accurate prognostic stratification remains challenging in non–small cell lung cancer (NSCLC). Beyond TNM staging, biomarkers reflecting tumor biology may improve risk assessment. The Ki-67 proliferation index and maximum standardized uptake value (SUVmax) derived from 18F-fluorodeoxyglucose positron emission tomography–computed tomography (18F-FDG PET/CT) represent tumor proliferative and metabolic activity; however, their combined prognostic significance in NSCLC remains incompletely defined. Methods This single-center retrospective study included 205 patients with newly diagnosed NSCLC between January 2017 and April 2024 who underwent 18F-FDG PET/CT and had immunohistochemical assessment of Ki-67. Patients were stratified according to Ki-67 levels (≤ 10% vs. > 10%) and SUVmax values (≤ 2.5 vs.> 2.5). Associations with clinicopathologic characteristics were analyzed. Overall survival (OS) was evaluated using Kaplan–Meier analysis, and correlations between variables were assessed using Pearson correlation analysis. Results High Ki-67 (> 10%) and high SUVmax (> 2.5) were significantly associated with adverse clinicopathologic features, including male sex, smoking history, larger tumor size, higher tumor grade, advanced stage, and unfavorable histologic subtypes. SUVmax showed a significant positive correlation with Ki-67 (r = 0.278, p < 0.001 ) and tumor size (r = 0.371, p < 0.001 ). Kaplan–Meier analysis demonstrated significantly shorter OS in patients with high Ki-67 (log-rank p = 0.002 ) and high SUVmax (log-rank p = 0.033 ). Conclusions Ki-67 proliferation index and SUVmax are associated with aggressive tumor characteristics and poorer survival in NSCLC. The combined evaluation of metabolic and proliferative biomarkers, together with established clinical factors, may improve prognostic stratification. Prospective multicenter studies are warranted to further clarify the clinical utility of these parameters.