The relationship between inflammatory indices and metabolic parameters on PET-CT in patients diagnosed with extensive stage small cell lung cancer

Introduction: Small cell lung cancer (SCLC) is a malignancy with a rapid course and high metastatic potential. Due to the rapid course of the disease, it is important to determine prognostic factors. In this study, we aimed to show the relationship between inflammatory indices and metabolic parameters measured by 18F Fluorodeoxyglucose Positron Emission Tomography Computed Tomography (18F FDG PET-CT) and to evaluate the effects of these parameters on the survival of patients with SCLC. Methods: This study was a retrospective review of 110 patients diagnosed with SCLC at Çukurova University Faculty of Medicine between April 28, 2011 and August 9, 2023. Demographic data, laboratory values and imaging findings were recorded. Prognostic nutritional index (PNI), platelet albumin ratio (PAO) and albumin alkaline phosphatase ratio (AAFO) values, which we consider as inflammatory index, were recorded. 18F FDG PET-CT images of the patients were evaluated by the Department of Nuclear Medicine and maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG) values were recorded. Results: There was a weak positive correlation between SUVmax and SUVmean values and PAO values (r=0.27; r=0.247, respectively) (p<0.05), and a weak negative correlation between MTV and TLG values and AAFO values (r=-0.243; r=-0.234, respectively) (p<0.05). Survival analyses of the patients were analyzed in two groups according to early mortality and late mortality and it was found that the mean survival times of the patients in the high MTV and low PNI group were lower according to the cut-off values determined. Conclusion: There was a weak positive correlation between inflammatory indices and 18F FDG PET-CT metabolic parameters SUVmax, SUVmean and PAO values, and a weak negative correlation between MTV and TLG values and AAFO values. Keywords: Small cell lung cancer, platelet albümin ratio, albümin alkaline phosphatase ratio, metabolic tumor volume, total lesion glycolysis