The value of preoperative FDG PET/CT in detecting groin metastases in vulvar cancer patients

Abstract

Objective: This retrospective study aimed to evaluate the diagnostic value of preoperative18F-Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in detecting groin Lymph Node (LN) metastases in newly diagnosed vulvar cancer patients. Methods: In the period 01.01.2014 to 31.12.2018, we retrospectively collected data by reviewing the medical record of 237 patients with diagnosed vulvar cancer referred to Aarhus University Hospital. In the study, 108 patients were included for final analysis. Inclusion criteria was that all women should have histology from the groin with either Inguinofemoral Lymph Node (IFLN) dissection, Sentinel Lymph Node (SLN) procedure or Ultrasound (US)-guided biopsy. In addition, all included patients underwent FDG PET/CT for primary staging of vulvar cancer before operation. Sensitivity, specificity, Positive and Negative Predictive Values (PPV and NPV) in predicting LN metastases were calculated in the overall study population. Results from FDG PET/CT were compared with histopathology as reference standard. Results: All included women underwent a standardized patient investigation program. This included a thorough gynecological examination, a Magnetic Resonance Imaging (MRI) and FDG PET/CT scan. We found that PET/CT had a sensitivity of 90.9% (95% CI 70.8-98.9%), specificity of 67.4% (95% CI 56.5-77.2%), PPV of 41.7% (95%CI 27.6-56.8%) and a NPV of 96.7% (95% CI 88.5-99.6%). Conclusion: In this relatively large single-center study, we found that FDG PET/CT has a high sensitivity and a high NPV in detecting LN metastasis in the groin. This supports, that FDG PET/CT is a valuable imaging modality in the management of vulvar cancer patients.