The Comparison of Three Different Malignacy Evaluation Criteria of Cervical Lymph Nodes in Oral Cavity Cancer Using F-18 Fdg Pet-Ct

Abstract

Aims: Our aim was to evaluate the diagnostic role of Fluorine-18 fluorodeoxyglucose Positron emission tomography-computed tomography (F-18 FDG PET-CT) using three different criteria published in the literature and to compare the diagnostic value of these three parameters in patients with oral cavity cancers (OCC). Materials and methods: 16 patients (4 female; 12 male, 29-81 years) were included in this study. Malignancy in the lymph nodes was evaluated according to these 3 criteria: 1: Visual assessment 2: The ratio of maximum standard uptake value (SUVmax) in tumor/ adjacent muscle tissue (T/M), 3: SUVmax adjusting to the size of lymph nodes. The histopathological evaluation of the surgery was recorded according to the neck levels. The sensitivity, specificity, negative predictive values (NPV) and positive predictive values (PPV) of F-18 FDG PET-CT for each malignancy criteria and receiver operating characteristic (ROC) curves were obtained for SUVmax and T/M. Results: Histopathological evaluations revealed 5 patients had metastatic lymph nodes (N+) whereas 11 patients had benign lymph nodes (N-). 14 of 43 lymph nodes that were visualized in CT of F-18 FDG PET-CT were evaluated as malignant whereas 29 of 43 lymph nodes were evaluated as benign. The average of SUVmax and T/M ratios of visually malignant lymph nodes were 7.67 +/- 4.95 and 7.10 +/- 3.18, respectively. The average of SUVmax and T/M ratios of visually benign lymph nodes were 1.69 +/- 0.43 and 1.49 +/- 0.48, respectively. The highest sensitivity, specificity, NPV and PPV were obtained in the criteria of T/M ratios with the threshold value of SUVmax (regardless from the size) as 3.4 and T/M ratio as 3.2 which is obtained from our population using ROC curve, 93% sensitivity, 96% specificity were calculated. Conclusion: This study indicates that F-18 FDG PET-CT is a reliable method for the correct evaluation of primary tumor and N staging in OCC. This study showed that T/M ratios in the lymph nodes could be used to evaluate malignancy with a highest diagnostic accuracy.