Evaluation of FDG-PET for detecting lymph node metastasis in uterine corpus cancer.

BACKGROUND In order to decrease surgery-related morbidity, we evaluated the reliability of the evaluation of lymph node metastasis in patients with uterine corpus cancer by positron-emission tomography (PET) with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) before surgical staging. MATERIALS AND METHODS Patients with newly diagnosed uterine corpus cancer scheduled for surgical staging, including lymphadenectomy, underwent PET imaging within 30 days before surgery. PET results and postoperative histopathology were compared for each patient and each nodal site. Sensitivity, specificity, positive and negative predictive value (PPV/NPV) as well as accuracy of FDG-PET in predicting nodal disease was determined by joined meta-analysis of the present data and the data available in the literature. RESULTS Of 21 patients examined, 13 patients were eligible to enter this pilot study. Only one patient had lymph node metastasis, which was preoperatively detected by FDG-PET scan. Additionally, another patient was considered to have lymph node metastasis according to increased focal FDG uptake; however, all lymph nodes were free of malignant disease upon final pathology. In contrast, all other patients without lymph node metastasis upon final pathology showed negative preoperative FDG-PET scans. The meta-analysis yielded a sensitivity, specificity, PPV, NPV and accuracy of 0.53, 0.91, 0.57, 0.90 and 0.84, respectively. CONCLUSION In patients with uterine corpus cancer, FDG-PET had an insufficient positive predictive value in detecting lymph node metastases, indicating that this method cannot replace surgical staging. However, due to its high NPV, FDG-PET might be beneficial in selected patients who are poor candidates for surgical staging.