Background: High risk clinical stage I endometrial cancer (grade 2 and deep myometrial invasion, grade 3 and serous and clear-cell carcinoma) had 10-35% of nodal involvement. Surgical staging is considered reasonable in this setting of women, although unnecessary in 70-90%. The purpose of this study was to determine prospectively the diagnostic accuracy of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography 18F-FDG PET/CT in the detection of nodal metastases in patients with high risk endometrial cancer.
Methods: Eleven women with grade 2 and deep myometrial invasion and 26 with grade 3 endometrial cancer underwent 18F-FDG PET/CT, followed by total hysterectomy, bilateral salpingo-oophorectomy and systematic pelvic lymphadenectomy. Histopathological findings served as the reference standard. Diagnostic performance of 18F-FDG PET/CT in nodal disease detection was reported in terms of accuracy value both in a patient-based and a lesion site-based analysis.
Results: Pelvic nodes metastases were found at histopathological analysis in 9 of the 37 patients (24.3%). Patient-based sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT for detection of nodal disease were 77.8%, 100.0%, 100.0%, 93.1% and 94.4%, respectively. Nodal lesion site-based sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT were 66.7%, 99.4%, 90.9%, 97.2% and 96.8%, respectively.
Conclusion: This study shows that 18F-FDG PET/CT is an accurate method for the presurgical evaluation of pelvic nodes metastases. The high negative predictive value may be useful in selecting patients who only may benefit from lymphadenectomy, minimizing operative and surgical complications.