Correlation of preoperative 18F-FDG-PET/CT tumor staging and maximum standardized uptake values with preoperative CT, postoperative tumor classification, and histopathological parameters of oral squamous cell carcinoma.

Abstract

Introduction: This study aimed to correlate preoperative 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) tumor staging, and maximum standardized uptake values (SUV_max) with preoperative CT data, postoperative tumor classification, and histopathological parameters of oral squamous cell carcinoma (OSCC).

Material and methods: Thirty-seven OSCC patients staged via full-body 18F-FDG-PET/CT, including contrast agent CT of the head and neck in 2020 and 2021, were enclosed. Patients received tumor resection and stage-dependent neck dissection. Preoperative clinical (c) 18F-FDG-PET/CT UICC tumor stages and TNM classifications were correlated to corresponding CT and to postoperative histopathological (p) UICC tumor stages and TNM classifications. SUV_max of the primary tumor was associated with pUICC and pTNM, including extranodal extension (ENE), perineural invasion (Pn), lymphatic spread (L), vascular invasion (V), tumor grading (G), and -thickness.

Results: Comparing 18F-FDG-PET/CT and CT, cUICC, cT, and cN differed in 32.3%, 16.7%, and 37.8% of the cases, respectively. For 18F-FDG-PET/CT, a moderate correlation was found between c- and pUICC (0.494; p = 0.0018) with a misestimation of c- compared to pUICC in 43.2% of the cases. Comparing c- and pTNM, misestimations concerning c- and pT were seen in 51.4% and concerning c- and pN in 37.8% of the cases. An increased SUV_max significantly correlated with increased pT- and pUICC (adjusted Odds ratio 1.103; p = 0.042 and 1.126; p = 0.021, respectively). The predictive quality of an SUV_max cutoff value for detecting cervical lymph node metastases and G was poor, as indicated by the low AUC values from the ROC analysis. No correlations were found between SUV_max and ENE, Pn-, L-, and V-status. A strong correlation was found between SUV_max and tumor thickness with an adjusted coefficient of 1.034 (p = 0.01).

Conclusion: The predictive value of 18F-FDG-PET/CT and SUV_max on histopathological tumor classification and parameters appears limited.

Clinical relevance: 18F-FDG-PET/CT can not unreservedly be recommended for primary OSCC staging. There is an urgent need to specify its indications in detail further.