The Role of PET-CT in Evaluation of Cervical Lymph Node Metastases in Oral Cavity Squamous Cell Carcinomas

Abstract

Objective: The aim of this study is to determine the sensitivity and specificity of positron emission tomography-computed tomography (PET-CT) in the evaluation of cervical lymph node metastasis in oral cavity squamous cell cancers (SCCs) and to determine the SUV-max values in differentiating reactive and metastatic lymph nodes as a supportive parameter.

Methods: In this study, 23 patients were included who were diagnosed with oral cavity SCC and treated with surgery between 2006 and 2013 in our department. All the patients were scanned with PET-CT during the pretreatment evaluation. Detailed pretreatment PET-CT (retention sites and SUV-max values) and histopathological examination results were obtained. SPSS 17.0 software package was used for statistical analysis of the data. Categorical measurement was summarized as number and percentage and continuous measurements as mean and standard deviation (median and minimum-maximum where necessary). Chi-square test or Fisher's test were used in the comparison of categorical variables. Compliance of methods was assessed by Kappa coefficient analysis. In this study, the advantages of PET-CT were determined by the calculation of sensitivity and specificity values with histopathological examination results considered as the gold standard, and SUV-max value was assessed by examining the area under the ROC curve. In all tests, the level of statistical significance was accepted as 0.05.

Results: The threshold value for SUV-max depending on the data of the histopathological examination and results of PET-CT of the 23 patients was 2.50. The reliability of this threshold was determined as AUC=0.819. In demonstrating neck metastasis in patients with cancer of the oral cavity, PET-CT has a sensitivity of 89% and specificity of 98%. Compliance between the histopathological examination and PET-CT for metastatic cervical lymph nodes was determined to be 0.416 by kappa coefficient analysis.

Conclusion: There was FDG uptake on PET-CT in the cervical lymph node regions of all patients with metastatic cervical lymph nodes. There were no metastases in any of the patients with no FDG retention. The sensitivity and specificity of PET-CT in determining cervical lymph node metastasis were 89% and 98%, respectively, with a threshold SUV-max value considered as 2.50 in patients with FDG retention.