Relation between tumor FDG uptake and hematologic prognostic indicators in stage I lung cancer patients following curative resection

Hematologic parameters of systemic inflammation are receiving attention as promising prognostic indicators in cancer patients. Here, we investigated the relation and compared the prognostic values of circulating blood cell-based parameters and tumor F-18-fluoro-2-deoxyglucose (FDG) uptake in patients with stage I nonsmall cell lung cancers (NSCLC). Subjects were 1034 patients with newly diagnosed stage I NSCLC who underwent FDG positron emission tomography/computed tomography (PET/CT) followed by curative resection. Total white blood cell (WBC) count, absolute neutrophil, lymphocyte and platelet counts, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) were obtained. Tumor FDG uptake was measured as SUVmax. WBC, neutrophil and lymphocyte counts, and NLR demonstrated weak but significant correlation to tumor SUVmax. Using the upper quartile as cutoff, patients with high tumor SUVmax had significantly higher WBC, neutrophil and lymphocyte counts, and greater NLR. There were 144 recurrences (13.9%) over a median follow-up of 29.5 months. On Cox proportional hazards regression analysis, WBC count, tumor SUVmax, age, gender, smoking, cell type, and tumor stage were significant univariate prognostic factors. On multivariate analysis, high tumor SUVmax (HR=2.22; 95% CI, 1.52-3.25; P<0.001), tumor stage 1B (HR=2.11; 95% CI, 1.47-3.01; P<0.001), and old age (HR= 1.03; 95% CI, 1.01-1.05; P=0.002) were significant independent predictors of poor survival. Finally, high tumor SUVmax remained a significant predictor of prognosis in both low and WBC count groups. Circulating blood counts showed significant correlation to tumor FDG uptake in early stage NSCLC. WBC count was a significant univariate variable, but tumor FDG uptake was a superior and independent predictor of outcome. Hence, tumor FDG uptake effectively stratified prognosis in patients with low as well as high WBC count.