Complementary role of 18F-FDG PET/CT for sentinel lymph node algorithm in endometrial cancer with high-risk factors for lymphatic metastasis

Abstract

Objective National Comprehensive Cancer Network (NCCN) sentinel lymph node (SLN) algorithm includes ‘mandatory steps’ for evaluating pelvic lymph nodes, but assessment of paraaortic area is left to surgeon’s discretion. In this study, we aimed to investigate the complementary role of preoperative 18F-FDG PET/computed tomography (CT) scan in detecting pelvic and especially paraaortic lymphatic metastasis in endometrial cancer patients with high-risk factor(s) according to Mayo Clinic Criteria and underwent SLN algorithm. Methods Patients who underwent preoperative 18F-FDG PET/CT scan, intraoperative SLN algorithm followed by systematic lymphadenectomy (LND) and had at least one high-risk criterion for lymphatic metastasis were included in this study. 18F-FDG PET/CT and SLN algorithm were compared with final histopathological results of systematic LND. Results Thirty-eight patients were eligible for the study. Lymphatic metastasis was seen in 10 patients (26.3%). Four cases had paraaortic lymphatic metastases which were together with pelvic (n:2) or isolated (n:2) metastases. SLN algorithm was able to detect all pelvic lymph node metastases. However, isolated paraaortic metastases were diagnosed only by 18F-FDG PET/CT. In 76 hemipelvises, sensitivity and negative predictive value of SLN algorithm for diagnosis of pelvic nodal metastasis were 100%, while sensitivity, specificity, positive predictive value and negative predictive value of 18F-FDG PET/CT were 45.4, 95.3, 62.5 and 91.1%, respectively. Conclusions Although SLN algorithm has an excellent diagnostic value for pelvic nodal metastasis, paraaortic metastasis might be underdiagnosed. 18F-FDG PET/CT may be a feasible tool to exclude paraaortic lymphatic metastasis in high-risk patients for lymphatic metastasis who will undergo SLN algorithm.

Sentinel Lymph Node Mapping in Endometrial Cancer: A Comprehensive Review

“…Researchers from Korea showed that a sequential administration of bilateral uterine cornus injection of ICG followed by cervical injection, improved the para-aortic SLN detection rate from 5.7% to 38.2% in upper para-aortic area (p<0.001) and 18.7% to 67.1% in lower para-aortic area (p<0.001), which in turn identified more metastatic SLN in aortic area (7.9% vs. 2.4%) (p=0.070) ( 157 ). Researchers from Italy and Turkey suggest the addition of preoperative PET-CT in favor of PALAD decision ( 111 , 113 , 158 ). Taskin included 38 high-risk patients.…”

Initial experience with positron emission tomography/computed tomography in addition to computed tomography and magnetic resonance imaging in preoperative risk assessment of endometrial cancer patients

“…Taskin et al recently evaluated the complementary role of PET/CT in the sentinel lymph node algorithm in high-risk patients. In their study of 38 patients, two out of 10 patients with lymph node metastases had isolated paraaortic metastases diagnosed only on PET/CT [31].…”

Recent management of endometrial cancer: a narrative review of the literature

“…The incidence of para-aortic metastases is 51% when pelvic lymph nodes are positive, but it dramatically decreases to 3% when pelvic lymph nodes are negative ( 61 ). Some authors have proposed the implementation of PET-CT in the preoperative set-up for the assessment of the para-aortic space ( 105 , 106 ), however the survival benefit from para-aortic lymphadenectomy remains controversial. The above-mentioned problem for the SLN in the para-aortic space could be addressed by using other tracer injections sites or a combination of them.…”