EP-1381: Role of Metabolic Tumor Volume and Total Lesion Glycolysis on FDG-PET/CT in NSCLC treated with SBRT

Background:Recently, there are many reports from Japan about methotrexate associated lymphoproliferative disorder (MTX-LPD). We are investigating the predictive factor of spontaneous regression (SR) in MTX-LPD. On the other hand, FDG-PET/CT is used for diagnosis of LPD including malignant lymphoma. In addition, it was reported that imaging biomarkers such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG) could predict the prognosis of malignant tumor (1, 2). However, there is no report that these imaging biomarkers could predict the SR of MTX-LPD.Objectives:We investigate the usefulness of FDG-PET/CT for predictive factor of SR in MTX-LPD.Methods:We enrolled 24 RA patients who diagnosed MTX-LPD and performed FDG-PET/CT from 2005 to 2019. We divided these cases into spontaneous regression cases (SR group; 15 cases) and cases that treated with chemotherapy after MTX discontinuation (CTx group; 9 cases), and compared the difference as follow subjects between two groups; clinical data including histopathological findings, SUVmax to evaluate malignant tumor activity by FDG-PET/CT, MTV and TLG which refer to metabolically active volume of the tumor segmented FDG-PET/CT. In addition, we analyzed cut off levels, sensitivity and specificity using statistical software JMP.Results:Diffuse large B cell lymphoma (DLBCL) and Hodgkin lymphoma (HL) were 5 and 1 cases in SR group, and 1 and 5 cases in CTx group. In addition, MTV and TLG by FDG-PET/CT was significantly lower in SR group, although SUVmax is no difference between two groups (figure 1). Cut off levels of MTV and TLG were 103.12 ml (sensitivity; 88.9%, specificity; 86.7%) and 361.75 ml (sensitivity; 88.9%, specificity; 86.7%), respectively.Conclusion:We suggested that MTV and TLG were useful for predict of SR in MTX-LPD.References:[1]Chen HH, Chiu NT, Su WC. et al. Prognostic value of whole-body total lesion glycolysis at pretreatment FDG PET/CT in non-small cell lung cancer. Radiology. 2012 Aug;264(2):559-66.[2]Chu KP, Murphy JD, La TH. et al. Prognostic value of metabolic tumor volume and velocity in predicting head-and-neck cancer outcomes. Int J Radiat Oncol Biol Phys. 2012 Aug 1;83(5):1521-7.Figure 1.Comparison of the level of MTV(a) and TLG (b).Disclosure of Interests:None declared

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PET/CT Parameters are Useful in Discrimination of Incidental Benign, Premalignant and Malignant Colonic Lesions

Nuklearmedizin ◽

10.1055/a-1084-4723 ◽

2020 ◽

Vol 59 (03) ◽

pp. 235-240

Author(s):

Emine Budak ◽

Ahmet Yanarateş

Keyword(s):

Tumor Volume ◽

Standardized Uptake Value ◽

Metabolic Tumor Volume ◽

Total Lesion Glycolysis ◽

Premalignant Lesions ◽

Benign Lesions ◽

Pet Ct ◽

Malignant Lesions ◽

Fdg Pet Ct

Abstract Aim The present study evaluates the role of PET parameters pertaining to incidentally detected foci of colorectal uptake (IFCU) on FDG PET/CT in the differentiation of benign, premalignant and malignant lesions. Methods This retrospective study included 74 patients. The colonoscopic and histopathological findings were regarded as the reference standards. The results were evaluated on a lesion basis by dividing the lesions into three groups as benign, premalignant and malignant. The maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume(MTV) and total lesion glycolysis(TLG) values of the three groups were compared. Results There were 88 IFCU in a total of 74 patients (27 female, 47 male, mean age 65 years). Of the 88 IFCU, 26 were qualified as benign, 42 as premalignant and 20 as malignant. Malignant + premalignant lesions were found in 62/88 (70.4 %) of the IFCU. The SUVmax of the benign lesions was significantly lower than those of the premalignant and malignant lesions; and SUVmean was lower than that of the malignant lesions. The MTV of the malignant lesions was significantly higher than that of the premalignant and benign lesions; and TLG was higher than that of the premalignant lesions. The optimum cut-off value in differentiating between the malignant and non-malignant lesions was 9.15 for SUVmax, 5.05 for SUVmean, 4.7 for MTV and 30.25 for TLG. Conclusion PET parameters can guide the differentiation of benign, premalignant and malignant lesions with IFCU. Besides, patients with IFCU should undergo further evaluation due to high probability of premalignant and malignant lesions.

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