Objective: To study 18F-FDG PET/CT findings in endometrial cancer patients, to analyze the correlation between the
maximum standardized uptake value (SUVmax) and clinicopathologic tumor characteristics.
Material and Method: Retrospective study included 33 endometrial cancer patients who underwent pre-operative 18F-FDG PET/CT and abdominal CT or MRI from June 2005 to October 2009. Pattern of FDG uptake was classified as focal and diffuse uptake. SUVmax was measured at primary tumor in endometrial cavity and correlated with maximum tumor size, menopausal state, histological grade, depth of myometrial invasion and nodal metastasis. The diagnostic performance of 18FFDG PET/CT was assessed for primary tumor and lymph node metastasis and correlated with those of CT/MRI.
Results: Sensitivity of 18F-FDG PET/CT in primary tumor detection was slightly higher, without significant difference, than that of either CT or MRI (93.9 % vs. 87.9%, p = 0.625). The overall SUVmax mean of the primary tumor was 8.24+5.38. The focal FDG uptake pattern was more common than the diffuse uptake pattern (71.0% and 29.0%, respectively), but the SUVmax was higher in the diffuse uptake pattern (diffuse pattern 12.10+7.47 vs. focal pattern 6.66+3.33, p = 0.008). There was significant association between the SUVmax of the primary tumor and maximum tumor size (p = 0.001), but not between the SUVmax of the primary tumor and menopause state, histological grade, depth of myometrial invasion and nodal metastasis (p = 0.522, 0.622, 0.694 and 0.601, respectively). For lymph node detection, the sensitivity of 18F-FDG PET/CT were also higher, without statistically significant difference, than those of CT/MRI (on patient basis; 80.0% vs. 40.0%, p = 0.500; on nodal basis 64.7% vs. 47.1%, p = 0.453, respectively).
Conclusion: 18F-FDG PET/CT had slightly higher diagnostic sensitivity than CT/MRI in both primary tumor and lymph node detection. The finding focal uptake pattern is more common, but the diffuse uptake pattern shows higher FDG uptake. The SUVmax of primary tumors was associated with the maximum tumor size, but not associated with menopause state, histologic grade, depth of myometrial invasion and nodal metastasis.

Keywords: Endometrial cancer, 18F-FDG, PET/CT, Maximum standardized uptake value