Prognostic Value of 16α-F-Fluoro-17β-Estradiol PET as a Predictor of Disease Outcome in Endometrial Cancer: A Prospective Study.

The purpose of this study was to evaluate the potential of 16α-F-fluoro-17β-estradiol (F-FES) PET to predict prognosis in patients with endometrial cancer (EC). In total, 67 patients with International Federation of Gynecology and Obstetrics (FIGO) stage I-IV EC underwent F-FES and F-FDG PET/CT before treatment. The SUV of the primary tumor was compared with the clinical characteristics, and the relationships between SUV and progression-free survival (PFS) or overall survival were analyzed. F-FES SUV was significantly associated with stage, histology, lymphovascular space involvement (LVSI), and lymph node metastasis, and F-FDG SUV was significantly associated with stage, myometrial invasion, tumor size, and lymph node metastasis. Receiver-operating characteristic curve analysis revealed that F-FES SUV could significantly detect tumor progression and survival, with areas under the curve of 0.813 and 0.790, respectively, whereas F-FDG SUV could detect them with areas under the curve of 0.557 and 0.635, respectively. The Kaplan-Meier survival curve showed that patients with a low F-FES SUV had significantly poor PFS ( < 0.001) and overall survival ( = 0.001) compared with patients with a high SUV, whereas F-FDG showed no significant differences. In a subanalysis of 27 patients with a low risk of recurrence (FIGO stage IA endometrioid carcinoma [grade 1 or 2] without LVSI), those with a low F-FES SUV also had poorer PFS than those with a high SUV ( = 0.002). In multivariate analysis, an F-FES SUV of less than 2.63 ( 0.037; hazard ratio, 10.727; 95% CI, 1.16-99.35) and FIGO stages III and IV ( 0.042; hazard ratio, 8.838; 95% CI, 1.09-71.84) were significantly associated with PFS. A low F-FES for the primary tumor was strongly associated with prognostic factors of EC such as LVSI and lymph node metastasis, and a low F-FES SUV was an independent prognostic factor for PFS in patients with EC. These data suggest that pretreatment F-FES PET might be useful in determining the appropriate treatment for patients with EC.