According to the sentinel node biopsy (SNB), systematic pelvic lymph node dissection (PLND) may not be needed for patients with early-stage endometrial cancer. On the other hand, imaging technology including fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has been developing worldwide. The aim of this study was to evaluate the combined diagnostic accuracy of FDG PET/CT and SNB in the prediction of pelvic lymph node metastasis in endometrial cancer patients.
One hundred twenty-one patients with endometrial cancer underwent FDG PET/CT before hysterectomy and received SNB followed by systematic PLND. Univariate and multivariate analyses were performed to compare the diagnostic accuracy of FDG PET/CT and SNB in the prediction of pelvic node metastasis to the ultimate histologic status.
FDG PET/CT had lower sensitivity (36.8% versus 57.9%, P = .1) and a higher specificity (96.4% versus 84.8%, P < .01) than SNB. The kappa statistics of FDG PET/CT and SNB were 0.37 (95% CI, 0.15–0.59) and 0.72 (95% CI, 0.53–0.90), respectively. The sensitivity of SNB was significantly higher than that of FDG PET/CT in all hemi-pelvises (HPs) in which the short axis of the largest metastatic lymph node was <5 mm in diameter (72.7% versus 18.2%, P = .01). In contrast, the sensitivity of FDG PET/CT was higher than that of SNB in all HPs in which the short axis of the largest metastatic lymph node was ≥5 mm in diameter (62.5% versus 37.5%, P = .2); however, the difference was not statistically significant. When the combined diagnosis of FDG PET/CT and SNB was made, the sensitivity and specificity were 84.2% and 82.1%, respectively.
SNB was more useful for detecting lymph node metastasis than FDG PET/CT, especially in patients with small metastatic lymph nodes. The combined diagnosis of FDG PET/CT and SNB improves the sensitivity; PET-positive nodes should be dissected regardless of SNB status and HPs in which SNB was not detected should be dissected systematically regardless of FDG PET/CT status.