Purpose: To clarify prospectively the relationship between estrogen receptor (ER) expression and glucose metabolism by using 16alpha-[(18)F]fluoro-17beta-estradiol (FES) and fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients with benign and malignant uterine tumors.
Materials and methods: The institutional review board approved this study, and informed consent was obtained from all subjects. FES and FDG PET studies were performed in 38 patients (mean age, 54.1 years +/- 14.0 [standard deviation]) with benign and malignant uterine tumors to compare differences in tracer accumulation. Regional values of tracer uptake were evaluated by using standardized uptake value (SUV), a normalized value corrected by using injection dose and body weight.
Results: Patients with endometrial carcinoma showed significantly greater mean SUV for FDG (9.6 +/- 3.3) than for FES (3.8 +/- 1.8) (P < .005). Patients with endometrial hyperplasia showed significantly higher mean SUV for FES (7.0 +/- 2.9) than for FDG (1.7 +/- 0.3) (P < .05). Patients with leiomyoma showed significantly higher mean SUV for FES (4.2 +/- 2.4) than for FDG (2.2 +/- 1.1) (P < .005), and patients with sarcoma showed opposite tendencies for tracer accumulation. Tracer uptake in patients with endometrial carcinoma was significantly higher for FDG (P < .001) and significantly lower for FES (P < .05) when compared with values in patients with endometrial hyperplasia. On the other hand, patients with sarcoma showed a significantly higher uptake for FDG (P < .005) and a significantly lower uptake for FES (P < .05) compared with patients with leiomyoma.
Conclusion: ER expression and glucose metabolism of uterine tumors measured by using PET showed opposite tendencies. PET studies with both FES and FDG could provide pathophysiologic information for the differential diagnosis of uterine tumors.