Association of PET Scan Parameters of Pulmonary Masses and Reticuloendothelial System with Hematologic Parameters

Abstract

Objectives: The most active organs of the reticuloendothelial system (RES) are the liver, spleen and bone marrow, having immune mechanisms against malignancy including neutrophils and platelets. RES may be imaged by different modalities, like PET scan. Neutrophil lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR) have gained importance as proinflammatory markers in cancer, e.g. lung cancer. The aim of this study was to investigate the relationship between PET parameters of pulmonary mass or RES, and hematological parameters, and to evaluate the role of these factors in differentiating the pathological character of the mass. Methods: A retrospective analysis of the data of 131 patients, retrieved from the department archives, with pulmonary mass limited to mediastinum was made. Patients were grouped according to pathological results: benign mass (n=46), squamous cell carcinoma (n=38), and non-squamous cancer of lung (n=47). All patients underwent PET/CT scanning and images were analyzed retrospectively. Maximum and mean SUV were calculated from primary lesions and RES. NLR and PLR were calculated from CBC. Results: SUVmax and SUVmean of RES organs were similar for both groups with benign and malignant pulmonary masses, and among the subgroups. SUVmax ratios of pulmonary mass were significantly different between the groups (the highest value in the squamous cell carcinoma and the lowest in the benign groups). No significant difference was determined between the subgroups for NLR and PLR. NLR was significantly correlated with SUVmax ratios of spleen and the mass, and SUVmean ratios of spleen and bone marrow. PLR was significantly correlated with SUVmax ratios of spleen, bone marrow, the mass and SUVmean ratios of spleen, bone marrow. Conclusion: SUV of RES and primary mass were correlated with NLR and PLR, indicators of systemic inflammation. The associations between NLR and PLR, and SUV should be clearly defined by further investigations.