Positron emission tomography with the glucose analog [18F]‐fluoro‐2‐deoxy‐D‐glucose for evaluating pelvic lymph node metastasis in uterine corpus cancer: Comparison with CT and MRI findings

Objective:  The aims of this study were to investigate the ability of positron emission tomography (PET) with the glucose analog [18F]-fluoro-2-deoxy-D-glucose (FDG) to detect pelvic lymph node metastasis of uterine corpus cancer and to perform a retrospective comparison with computed tomography (CT) and magnetic resonance imaging (MRI) findings. Methods:  Forty-six patients with uterine corpus cancer scheduled for surgery, including bilateral pelvic and/or para-aortic lymphadenectomy, were eligible for this study. CT and MRI of the pelvis and abdomen were performed in all patients within 2 weeks preceding whole-body FDG-PET. FDG-PET images were analyzed visually for objective assessment of regional tracer uptake. The sensitivity and specificity of each imaging modality for detecting pelvic lymph node metastasis were determined, respectively. Results:  Eleven (7 with myometrial invasion less than 1/2, 4 with myometrial invasion over 1/2) of the 46 patients (23.9%) were revealed to have pelvic lymph node metastasis. The sensitivity and specificity for detecting pelvic lymph node metastasis in patients with uterine corpus cancer by FDG-PET were 31.3% and 96.1% by lymph node region, respectively, and 36.4% and 91.4% by patient, respectively. No significant difference was noted among each imaging modality with sensitivity or specificity. Moreover, the sensitivity and specificity for detecting pelvic lymph node metastasis in 29 patients with endometrioid adenocarcinomas by FDG-PET were 28.6% and 96.1% by lymph node region, respectively, and 50% and 92% by patient, respectively. No significant difference was noted among each imaging modality in terms of sensitivity or specificity. Among 11 patients with pathologically positive pelvic lymph node metastasis, three out of four patients with myometrial invasion over 1/2 were diagnosed as pelvic lymph node metastasis positive by all diagnostic modalities, however, only one of seven patients with myometrial invasion less than 1/2 was diagnosed as pelvic lymph node metastasis positive by PDF-PET and CT. MRI could not detect pelvic lymph node metastasis in patients with myometrial invasion less than 1/2. Conclusions:  We suggest that current imaging modalities including FDG-PET cannot change medical management of patients with uterine corpus cancer before surgery.