Clinical Value of ¹⁸F-FDG PET/CT Quantitative Analysis in Risk stratification of Endometrial Carcinoma

Objectives: To explore the value of quantitative parameters of PET/CT imaging in predicting the risk stratification of endometrial carcinoma (EC) preoperative. Methods: The 37 patients with histologically confirmed EC were underwent preoperative PET/CT imaging. The quantitative parameters (SUVmax, metabolic tumor volume (MTV) & total lesion glycolysis (TLG)) of the primary lesion were evaluated respectively. The patient’s histopathology was collected after surgery. According to the European Society for Medical Oncology in proposed risk stratification standards, the histological grade 1 or 2 (G1/G2), invasion of less half of the myometrium (MI<1/2) & stage I were recognized as the low-risk group, otherwise as the high-risk group. Results: (1) MTV & TLG of the primary lesion had a positive correlation with MI, LVSI & high-risk degree (P<0.05). The rate of lymph node metastasis was significantly higher in MI≥1/2 & lymph vascular space involvement (LVSI) (+) than that in MI <1/2 & LVSI(-). Optimal cutoffs for SUVmax, MTV and TLG of the primary lesion in predicting deep myometrial invasion are 14.9, 10 & 66.4 respectively. The areas under the ROC curves (AUCs) are 0.718, 0.821 & 0.827, respectively (P=0.031,P=0.001&P=0.001). The TLG is superior to SUVmax in predicting deep myometrium invasion (P=0.039). (2).The values of MTV & TLG of the primary lesion were significantly higher in patients with high-risk group than those in low-risk group, but there was no significant difference of SUVmax in primary lesion between two groups. The areas under the ROC curves (AUCs) of MTV &TLG for distinguishing high-risk from low-risk carcinoma are 0.74 & 0.73 respectively. (P=0.013 & P=0.015). Optimal cut-off values of MTV&TLG are 9.4 & 50.0 respectively, determined by ROC analysis. Their sensitivity & specificity are 68.4%, 83.3% & 78.9%, 77.8%. The TLG of the primary lesion is superior to the SUVmax in predicting high-risk group (P=0.032). Conclusions: TLG of the primary lesion is superior to SUVmax in predicting MI≥1/2 & high-risk group. MTV & TLG of the primary lesion are superior to SUVmax in predicting risk stratification of EC patients.