Quantitative analysis of metabolic parameters at 18F‑fluorodeoxyglucose positron emission tomography in predicting malignant potential of anterior mediastinal tumors

Abstract

To evaluate the utility of 18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) for predicting the malignancy of anterior mediastinal tumors, the present study retrospectively examined a total of 105 consecutive patients who underwent surgical resection of anterior mediastinal tumors at Gunma University Hospital after undergoing a preoperative FDG-PET scan. Patients were divided into benign and malignant groups in accordance with the following three classification systems: i) Clinical classification, benign or malignant (thymoma and carcinoma); ii) recurrence-based classification, low-risk recurrence (benign and low-risk thymoma) or high-risk recurrence (high-risk thymoma and carcinoma); and iii) pathological classification, benign (benign and thymoma) or malignant (carcinoma). The present study analyzed the differences between the benign and malignant groups in terms of FDG-PET parameters, including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG). The malignant group exhibited a significantly greater SUVmax than the benign group according to all classification systems. By contrast, there was only a slight difference between groups in volume-based metabolic parameters (MTV and TLG) using the clinical classification, and no intergroup differences using the recurrence-based and pathological classifications. The area under the curve in receiver-operating characteristic curve analysis for predicting malignancy was significantly greater for SUVmax than for volume-based metabolic parameters using all classification methods. The respective optimal cutoff value, sensitivity and specificity of SUVmax to predict malignancy were 1.77, 92.0 and 87.0% for the clinical classification, 2.54, 93.6 and 60.3% for the recurrence-based classification, and 5.15, 78.9 and 90.7% for the pathological classification. SUVmax was the most useful parameter for predicting the malignancy of anterior mediastinal tumors.

Advantages of additional PET vs. MRI in the clinical diagnosis of anterior mediastinal tumors

“…Numerous studies reported the utility of PET for the diagnosis of malignant anterior mediastinal tumors (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Due to increased glucose metabolism, malignant tissues typically demonstrate higher FDG uptake compared with benign and normal tissue.…”

“…The utility of PET for the clinical diagnosis of malignant tumors, including thymoma and thymic cancer, has been reported in numerous publications (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Fluorodeoxyglucose (FDG) accumulation in high-risk thymoma, particularly thymic carcinoma, is evidently greater compared with in low-risk thymoma (10)(11)(12)(13)(14)(15)(16)(17)(18)20). The role of fluorodeoxyglucose-positron emission tomography (FDG-PET) in differentiating benign and malignant thymic masses has been previously evaluated by several small-scale studies (21).…”

Multiparameter diagnostic model based on 18F-FDG PET and clinical characteristics can differentiate thymic epithelial tumors from thymic lymphomas

“…Although several studies have described the 18 F-FDG PET or PET/CT values in the diagnosis of mediastinal tumors, to our knowledge, most studies have analyzed some types of these tumors [ 17 , 20 – 22 ],and there were few systematic descriptions of thymic tumors and comparisons between TETs and thymic lymphomas [ 23 ]. Most studies only rely on PET metabolic parameters for analysis, ignoring the differences in patients’ baseline characteristics and clinical symptoms.…”

“…Although several studies have described the 18 F-FDG PET or PET/CT values in the diagnosis of mediastinal tumors, to our knowledge, most studies have analyzed some types of these tumors [17,[20][21][22],and there were few systematic descriptions of thymic tumors and comparisons between TETs and thymic lymphomas [23].…”