F-18 Fluoro-D-glucose (FDG)-positron Emission Tomography (PET)/computed Tomography (CT) in Planning of Surgery and Sentinel Lymph Node Screening in Vulvar Cancers

Purpose: To determine the effectiveness of FDG-PET/CT in the assessment of inguinofemoral lymph node (IFLN) in patients with vulvar cancer by comparing FDG-PET/CT results, sentinel lymph node (SLN) screening with gamma probe, and the results of frozen section and definitive pathology in these lymph nodes.

Study Design: This prospective study included eight patients, who were diagnosed with vulvar cancer at the Gynecology and Obstetrics Department of Erciyes University, Turkey. All patients underwent FDG-PET/CT before surgery. Local excision and IFLN dissection were planned by assessing IFLN involvement with SLN screening with Tc-99m nanocolloid plus frozen section. Intraoperatively, SLN screening was performed by using a gamma probe, and these lymph nodes were excised and then evaluated by frozen section. Regardless of the frozen section results, the IFLNs were totally excised. The FDG-PET/CT scan results, SLN plus frozen section results and definitive pathology results of the inguinal lymph nodes were compared.

Results: The mean age was 64.50 ± 13.25 years (min-max 43-79 years). All tumors were squamous cell carcinomas. FDG-PET/CT scan determined vulvar lesions accurately in all patients (8/8; 100 %). When inguinal lymph nodes were assessed by FDG uptake and SUVmax values, lymph nodes were interpreted as reactive in four patients (4/8; 50 %) and metastatic in the others (4/8; 50 %). In all patients frozen section confirmed the FDG-PET-CT results and definitive histopathology results confirmed the frozen section and FDG-PET-CT results (8/8; 100 %).

Conclusions: In light of these data, FDG-PET/CT scanning is an effective method for the detection of primary tumor in vulvar cancer. Although it seems to be an effective method for the detection of IFLN metastasis, these findings must be supported by further studies with larger sample size for use in the planning of primary surgery and inguinal lymph node dissection without SLN dissection and frozen section, as a minimal invasive method.