Risk stratification of endometrial cancer and lymph node metastases prediction using 18F-FDG PET/CT: role of metabolic tumor volume and total lesion glycolysis

Abstract

Background: Endometrial cancer is the commonest gynecologic malignancy. Pelvic lymph node metastasis is considered one of its most important prognostic factors. Surgery is considered the most important and effective treatment, still there is controversy about indication and necessity of pelvic lymph node dissection. 18F-fluorodeoxyglucose positron emission tomography/computed tomography is investigated in his study to evaluate its value in preoperative detection of lymph node metastases and risk stratification of endometrial cancer. Results: Reviewing the records of 33 women with endometrial cancer, all 18F-FDG PET/CT studied indices, SUVmax, SUVmean, MTV and TLG, mean difference was statistically significant in all the studied risk categories (tumor grade, Myometrial invasion, lymphovascular space invasion, tumor stage, and risk stratification). SUVmax and TLG showed highest area under the curve for detection of Myometrial invasion > 50% (AUC = 0.911) with cut-off value of SUVmax > 14.55 showing 88.89% sensitivity and 86.67% specificity, and TLG > 192.653 having 88.89% sensitivity and 80% specificity. TLG showed highest AUC (0.889 and 0.921) for detection of LVSI and LNMs with 100% sensitivity and 66.67% specificity for cut-off value > 179.374 and 88.89% sensitivity and 83.33% specificity for cut-off value > 249.366, respectively. Concerning risk stratification of EC, SUVmax and TLG showed highest AUC (0.839) with cut-off value > 14.55 showing 77.27% sensitivity and 90.91% specificity, and > 192.653 having 77.27% sensitivity and 81.82% specificity, respectively. Conclusion: The results of this study suggest that 18F-FDG PET/CT is a very valuable tool for prediction of lymph node metastases and risk stratification in endometrial cancer patients. Applying TLG cutoff values increases the accuracy and preoperative diagnosis of lymph node metastases which aids in sparing women with low-risk early stage EC unnecessary surgical risk and morbidity of lymphadenectomy.