The utility of FDG PET/CT in investigating the imaging characteristics of esophageal cancer

Abstract

Introduction: PET/CT is an effective modality in the diagnosis and monitoring esophageal cancer (EC). This study aims to investigate the imaging characteristics of primary lesions, regional lymph node metastasis, and distant metastasis on FDG PET/CT images, as well as to analyze the correlation between metabolic activity indices and the invasiveness and metastasis of esophageal cancer.
Methods: A retrospective study described untreated primary EC patients who underwent FDG PET/CT imaging to investigate the imaging characteristics of lesions and assess the correlation between the metabolic activity of primary esophageal lesions and their invasiveness and metastasis.
Results: PET/CT identified all 76 primary esophageal lesions in 69 patients. The most common locations of primary lesions were the mid-thoracic esophagus (38.2%), while the least common was the abdominal esophagus (2.6%). Cancers invading adjacent organs were observed in 14/76 lesions, most frequently the trachea (6.6%), the thoracic aorta (5.3%) and the lungs (3.9%). The values for glucose metabolism in esophageal lesions were maxSUV=16.1±7.5; peakSUV=12.6±6.1; meanSUV=6.5±2.6; TLG=288.2±326.1; MTV= 41.1±41.6. 54/69 patients had regional lymph node metastases (78.3%) with the most common being the right upper paratracheal (10% of lymph nodes), upper thoracic paraesophageal (8.5% of lymph nodes) and middle thoracic paraesophageal (8.5% of lymph nodes). The glucose metabolism values for metastatic lymph nodes were maxSUV=9.9±5.9. PET/CT identified distant metastasis in 23 out of 69 patients (33.3%), with the most common being distant lymph node metastasis (15.9%) and bone metastasis (11.6%). Three cases (4.3%) had simultaneous metastasis
to two organs. The metabolic tumor volume (MTV) is correlated with the ability to invade adjacent organs (p<0.05) with an optimal cutoff value of MTV≥36.68 cm³ (sensitivity 71%, specificity 71%, AUC=0.73). Additionally, the total lesion glycolysis (TLG) cutoff threshold of ≥132.26 (sensitivity 71%, specificity 76%, AUC=0.71) and the metabolic tumor volume (MTV) of ≥17.47 cm³ (sensitivity 78%, specificity 65%, AUC=0.71) for primary esophageal lesions are significantly correlated

Conclusion: Esophageal cancer lesions often exhibit increased glucose metabolism on FDG PET/CT. PET/CT plays a crucial role in diagnosing primary lesion locations and detecting metastatic lesions. The metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are more strongly correlated with the invasiveness of primary lesions and the potential of regional lymph node metastasis compared to standard uptake values (SUV). with the potential of regional lymph node metastasis (p<0.05).