Prospective evaluation of FDG-PET for detecting pelvic and para-aortic lymph node metastasis in uterine corpus cancer

Abstract

Objectives To estimate the sensitivity and specificity of positron emission tomography (PET) with 2-[ 18F]fluoro-2-deoxy- d-glucose (FDG) for detecting pelvic and para-aortic lymph node metastasis in patients with uterine corpus carcinoma before surgical staging. Methods Patients with newly diagnosed FIGO grade 2 or 3 endometrioid, papillary serous, or clear cell adenocarcinoma or uterine corpus sarcoma scheduled for surgical staging, including bilateral pelvic and para-aortic lymphadenectomy, were eligible. PET was performed within 30 days of surgery and interpreted independently by two nuclear medicine physicians. The imaging, operative, and pathologic findings for each patient and each nodal site were compared, and the sensitivity and specificity of FDG-PET in predicting nodal metastasis were determined. Results Twenty patients underwent FDG-PET before surgical staging. One patient found to have ovarian carcinoma on final pathology was excluded. Of the 19 primary intrauterine tumors, 16 (84%) exhibited increased FDG uptake. One patient did not undergo lymphadenectomy; her chest CT was suspicious for metastatic disease and FDG-PET showed uptake in multiple nodal and pulmonary foci. Metastatic disease was confirmed by percutaneous nodal biopsy. A total of three pathologically positive nodes were found in 2 of the 18 patients (11%). FDG-PET predicted that 3 patients would have positive lymph nodes (2 true positive and 1 false positive). Analyzed by lymph node regions, FDG-PET had 60% sensitivity and 98% specificity. The sensitivity and specificity by individual patient were 67% and 94%, respectively. Conclusions FDG-PET is only moderately sensitive in predicting lymph node metastasis pre-operatively in patients with endometrial cancer. This imaging modality should not replace lymphadenectomy, but may be helpful for patients in whom lymphadenectomy cannot be, or was not, performed.