Potential of Lean Body Mass ¹⁸F-FDG PET/CT Parameters to Predict Pathologic Findings in Overweight Endometrial Cancer...

Endometrial cancer is the second most common gynaecologic cancer in women worldwide. Due to the biology of endometrial cancer, most patients are overweight. Standard uptake value (SUV) measurements are known to vary depending on the patient's body weight. We aimed to evaluate whether lean body mass-adjusted ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) parameters [lean body mass-corrected standardized uptake value (SUL)-based metrics] are superior to conventional SUV-based parameters for predicting adverse histopathologic features in overweight patients with endometrial cancer, and to explore their association with progression-free survival (PFS).

In this retrospective single-center study, 73 overweight patients with endometrial cancer who underwent preoperative ¹⁸F-FDG PET/CT followed by primary surgery were included. SUV- and SUL-based metabolic parameters were compared with histopathologic risk factors. ROC analyses were performed to determine discriminatory performance and optimal cut-off values. PFS was assessed using Kaplan-Meier analysis.

SUV_mean (SUL_mean) demonstrated significant associations with deep myometrial invasion, lymphovascular space invasion, lymph node involvement, and higher tumor grade. In ROC analysis, SUL_mean showed moderate discriminatory ability for lymph node involvement (area under the curve: 0.78). However, PFS did not differ significantly between groups stratified by the ROC-derived SUL_mean cut-off (log-rank p=0.46).

Lean body mass-adjusted PET parameters, particularly SUL_mean, were more strongly associated with adverse histopathologic features than conventional SUV metrics in overweight patients with endometrial cancer. Although SUL-based parameters may contribute to preoperative risk assessment, their prognostic value for survival remains uncertain.