Preoperative PET/CT does not accurately detect extrauterine disease in patients with newly diagnosed high-risk endometrial cancer: A prospective study

Background: The identification of extrauterine disease is critical to the management of patients with high-risk endometrial cancer. The purpose of the current study was to determine the accuracy of preoperative positron emission tomography (PET)/computed tomography (CT) in the detection of extrauterine disease. Methods: Women with high-risk endometrial cancer were enrolled prospectively and underwent preoperative PET/CT followed by surgery, including sentinel lymph node biopsy and lymphadenectomy. Primary tumor factors on PET/CT were correlated with lymph node pathology. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the detection of lymphadenopathy and peritoneal disease by PET/CT. Results: A total of 112 patients were enrolled and underwent PET/CT between April 2013 and May 2016, 108 of whom were evaluable. On PET/CT, 21 patients (19.4%) were found to have extrauterine disease, 18 (17%) had positive lymph nodes, and 8 (7%) had peritoneal disease. A total of 108 patients underwent surgery, 103 of whom (95%) underwent lymphadenectomy. The sensitivity of PET/CT to detect positive lymph nodes was 45.8%, with a specificity of 91.1%, positive predictive value of 61.1%, and negative predictive value of 84.7%. The false-negative rate was 54.2%. There was no difference in primary tumor characteristics on imaging noted between patients with positive and negative lymph nodes. The sensitivity of PET/CT to detect peritoneal disease was 37.5%, with a specificity of 97.8%, positive predictive value of 75%, and negative predictive value of 90.0%. The false-negative rate was 62.5%. Conclusions: Preoperative PET/CT did not reliably predict the presence of extrauterine disease in women with high-risk endometrial cancer. Given the high false-negative rates, PET/CT should not be used in the preoperative treatment planning of these patients.