A novel preoperative scoring system based on 18-FDG PET-CT for predicting lymph node metastases in patients with high-risk endometrial cancer

The purpose of this study was to develop a model predicting the probability of pelvic-paraaortic node metastases in high-risk endometrial cancer patients. This trial included 41 high-risk endometrial cancer patients. All of the patients underwent an 18-FDG PET-CT followed by surgical staging, including a pelvic and paraaortic lymphadenectomy. We developed a useful scoring system combining weighted risk factors derived from a regression model: (3 x presence PET-CT involvement) + (3 x PET-CT maximum standardised uptake value >= 20) + (2 x diabetes comorbidity) + (1 x age >= 60 years) + (1 x body mass index >= 30). The area under the curve of the resulting score was 0.848. There was 75% sensitivity, 89% specificity and a 75% positive predictive value and 89% negative predictive value when a score of 6 was used as the cut-off. Our novel preoperative scoring system is an accurate method for the preoperative evaluation of lymph node metastases, and thus will aid gynaecological oncologists in selecting EC patients who may benefit from a lymphadenectomy. Impact statement What is already known on this subject? Endometrial cancer (EC) is a common gynaecological malignancy. Surgical staging is currently the standard treatment and the gold standard for evaluating lymph node metastases (LNm) is a surgical assessment (Chan et al. 2006). Three previous randomised clinical studies failed to find a clear therapeutic role for the lymphadenectomy; thus, the utility of this surgical procedure in high-risk early-stage EC remains under debate (Benedetti Panici et al. 2008; Kitchener et al. 2009; Signorelli et al. 2015). Non-invasive techniques that accurately identify lymph node metastases would reduce costs and complications. What do the results of this study add? Our developed novel scoring system that is based on positron emission tomography-computer tomography (PET-CT) with 2-deoxy-2-(18F) flouro-2-D-glucose (FDG) may facilitate the identification of patients at an increased risk of LNm.