Evaluation of Dual-Timepoint ¹⁸F-FDG PET/CT Imaging for Lymph Node Staging in Vulvar Cancer

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Invasive vulvar cancer (VC) management relies on accurate lymph node (LN) staging.
• Inguinofemoral lymph node dissection is standard but associated with morbidity.
• Improved preoperative LN status prediction is crucial for treatment planning.

Purpose of the Study:

• To evaluate the utility of dual-timepoint ¹⁸F-FDG PET/CT in predicting LN metastasis in VC patients.
• To compare standard and delayed ¹⁸F-FDG PET/CT imaging performance.
• To determine if advanced imaging can guide surgical intervention selection.

Main Methods:

• Prospective enrollment of 33 VC patients undergoing inguinofemoral LN dissection.
• Whole-body ¹⁸F-FDG PET/CT performed at 1 hour (standard) and 3 hours (delayed) post-injection.
• Visual scoring and semiquantitative analysis (SUV_max, retention index) of LN uptake.
• Histopathology served as the reference standard for LN status.

Main Results:

• Of 57 dissected groins, 37% had metastatic LNs.
• Standard ¹⁸F-FDG PET/CT showed 95.2% sensitivity and 75% specificity for LN metastasis.
• Delayed scanning offered marginal improvements in specificity (77.8%) but not significant predictive value.
• SUV_max cutoff of 1.32 (standard) and 1.88 (delayed) were identified.

Conclusions:

• Standard ¹⁸F-FDG PET/CT is a valuable tool for preoperative LN staging in vulvar cancer.
• Accurate prediction of pathologically negative nodes can facilitate selection for minimally invasive surgery.
• Delayed imaging did not substantially enhance diagnostic performance in this cohort, warranting further investigation.